TW201635348A

TW201635348A - Process for doping semiconductors

Info

Publication number: TW201635348A
Application number: TW104144315A
Authority: TW
Inventors: 奧利佛多爾; 印格寇勒; 賽巴絲汀巴斯
Original assignee: 馬克專利公司
Priority date: 2014-12-30
Filing date: 2015-12-29
Publication date: 2016-10-01
Also published as: WO2016107662A1; CN107112381A; EP3241243A1; KR20170100628A; US20170372903A1; JP2018506180A

Abstract

The present invention relates to a process for the production of structured, highly efficient solar cells and of photovoltaic elements which have regions of different doping. The invention likewise relates to the solar cells having increased efficiency produced in this way.

Description

掺雜半導體之方法 Method of doping semiconductor

本發明係關於一種製造結構化、高效率之太陽能電池及製造具有不同摻雜的區域之光伏打元件之方法及組合物。本發明亦關於依此方式製造的具有提高之效率之太陽能電池。 The present invention relates to a method and composition for fabricating a structured, high efficiency solar cell and fabricating photovoltaic elements having regions of different doping. The invention also relates to solar cells having improved efficiency manufactured in this manner.

簡單的太陽能電池或目前代表市場上最大市場佔有率之太陽能電池的生產包括下文所概述之主要生產步驟： The production of simple solar cells or solar cells that currently represent the largest market share in the market includes the main production steps outlined below:

1)鋸狀損傷蝕刻及紋理化 1) saw-like damage etching and texturing

矽晶圓(單晶、多晶或準單晶，基區摻雜p或n型)藉由蝕刻方法及一般在相同蝕刻浴中「同時」紋理化而不具黏著鋸狀損傷。在此情況中紋理化意指產生因蝕刻步驟造成之優先排列表面性質或僅晶圓表面之刻意、但非特定排列之粗糙化。因紋理化之故，晶圓之表面現在充作漫反射體及因此減少定向反射，此取決於入射光之波長及角度，最終使得入射於表面上的光被吸收的比例增加及因此太陽能電池之轉換效率提高。 Tantalum wafers (single crystal, polycrystalline or quasi-single crystal, doped p or n in the base region) are "simultaneous" textured by etching methods and generally in the same etching bath without stick-like damage. Texturing in this case means creating a preferentially aligned surface property due to the etching step or only a deliberate, but non-specific, roughening of the wafer surface. Due to texturing, the surface of the wafer is now filled with a diffuse reflector and thus reduces directional reflection, depending on the wavelength and angle of the incident light, ultimately increasing the proportion of light incident on the surface that is absorbed and thus the solar cell Conversion efficiency is improved.

就單晶晶圓而言，上述用於處理矽晶圓之蝕刻溶液通常由已添加異丙醇作為溶劑之稀氫氧化鉀溶液組成。若此可實現所需蝕刻結果，則亦可改為添加其他的相較於異丙醇具有更高蒸氣壓或更高沸點之醇。達成的所需蝕刻結果通常為特徵係隨機配置或確切地說從原始表面蝕刻出的具有方底之棱錐體之形態。可藉由適宜地選擇上述蝕刻溶液之組分、蝕刻溫度及晶圓在蝕刻槽中之滯留時間而部分地影響棱錐體之密度、高度及因此部分地影響底面積。單晶晶圓之紋理化通常在70至低於90℃之溫度範圍內進行，其中每個晶圓側可藉由蝕刻移除多至10μm的材料。 In the case of a single crystal wafer, the above etching solution for treating a germanium wafer is usually composed of a dilute potassium hydroxide solution to which isopropanol has been added as a solvent. If this results in the desired etching results, it is also possible to add other alcohols having a higher vapor pressure or higher boiling point than isopropanol. The desired etch result achieved is typically in the form of a pyramid having a square bottom that is characterized by a random configuration or, in particular, etched from the original surface. The above etching can be suitably selected The composition of the solution, the etch temperature, and the residence time of the wafer in the etch bath partially affect the density, height, and thus the bottom area of the pyramid. The texturing of the single crystal wafer is typically performed at a temperature ranging from 70 to less than 90 ° C, wherein each wafer side can be removed by etching up to 10 μm of material.

就多晶矽晶圓而言，蝕刻溶液可由具有中等濃度(10至15%)之氫氧化鉀溶液組成。然而，此蝕刻技術仍很少用於工業實務中。更頻繁地，使用由硝酸、氫氟酸及水組成之蝕刻溶液。可藉由尤其能特別影響蝕刻溶液之潤濕性質亦及其蝕刻速率之各種添加劑，諸如(例如)硫酸、磷酸、乙酸、N-甲基吡咯啶酮亦及表面活性劑改良此蝕刻溶液。此等酸性蝕刻混合物在表面上產生出巢狀蝕刻溝槽之形態。該蝕刻通常在4℃與低於10℃之間之溫度下進行，及藉由本文蝕刻除去的材料的量一般為4μm至6μm。 For polycrystalline germanium wafers, the etching solution can consist of a potassium hydroxide solution having a moderate concentration (10 to 15%). However, this etching technique is still rarely used in industrial practice. More frequently, an etching solution composed of nitric acid, hydrofluoric acid, and water is used. The etching solution can be modified by various additives which particularly affect the wetting properties of the etching solution and its etching rate, such as, for example, sulfuric acid, phosphoric acid, acetic acid, N-methylpyrrolidone, and a surfactant. These acidic etching mixtures produce a pattern of nested etched trenches on the surface. The etching is usually carried out at a temperature between 4 ° C and less than 10 ° C, and the amount of material removed by etching herein is generally 4 μm to 6 μm.

於紋理化後立即用水充分地清潔矽晶圓並用稀氫氟酸處理以移除由於前面的處理步驟而形成的化學氧化物層及吸收及吸附於其中亦及其上之污染物，為隨後的高溫處理作準備。 Immediately after texturing, the silicon wafer is sufficiently cleaned with water and treated with dilute hydrofluoric acid to remove the chemical oxide layer formed by the previous processing steps and the contaminants absorbed and adsorbed therein and thereon, for subsequent Prepare for high temperature processing.

2)擴散及摻雜 2) Diffusion and doping

用由氧化磷組成之蒸氣在通常介於750℃與低於1000℃之間之高溫下處理經上一步驟(在此情況中，為p型基區摻雜)蝕刻並清潔之晶圓。在此操作中，在管狀爐中之石英管中將該等晶圓暴露於由乾燥氮氣、乾燥氧氣及磷醯氯組成之受控氛圍。為此目的，將該等晶圓引入至介於600與700℃之間之溫度的石英管中。輸送氣體混合物通過石英管。在輸送氣體混合物通過經強加熱之管期間，磷醯氯分解以提供由氧化磷(例如P₂O₅)及氯氣組成之蒸氣。氧化磷蒸氣尤其沉澱於晶圓表面(塗層)上。同時，矽表面在此等溫度下氧化並形成薄氧化物層。所沉澱的氧化磷嵌入該層中，引起二氧化矽與氧化磷之混合氧化物形成於晶圓表面上。該混合氧化物稱為磷矽酸鹽玻璃(PSG)。該PSG具有不同於氧化磷之軟化點及擴散常數，取決於存在的氧化磷之濃度而改變。該混合氧化物充作矽晶圓之擴散源，其中氧化磷在擴散過程中沿PSG與矽晶圓之間的界面方向擴散，於此情況中其藉由與晶圓表面處之矽反應而被還原為磷(矽熱法(silicothermally))。依此方式形成的磷具有在矽中相較在已形成其之玻璃基底中更高數量級的溶解度及因此由於極高偏析係數而優先溶解於矽中。溶解後，磷隨著濃度梯度擴散於矽中進入矽體積內。 The wafer etched and cleaned by the previous step (in this case, p-type base doping) is treated with a vapor consisting of phosphorus oxide at a high temperature typically between 750 ° C and less than 1000 ° C. In this operation, the wafers are exposed to a controlled atmosphere consisting of dry nitrogen, dry oxygen, and phosphonium chloride in a quartz tube in a tubular furnace. For this purpose, the wafers are introduced into a quartz tube at a temperature between 600 and 700 °C. The gas mixture is conveyed through a quartz tube. During piped through a gas mixture heated by the strong, phosphorus acyl chloride to decompose by oxidation of the phosphorus vapor (e.g. P ₂ O ₅₎ and consisting of chlorine. Phosphorus oxide vapors are especially deposited on the wafer surface (coating). At the same time, the surface of the crucible oxidizes at these temperatures and forms a thin oxide layer. The precipitated phosphorous oxide is embedded in the layer, causing a mixed oxide of cerium oxide and phosphorus oxide to be formed on the surface of the wafer. This mixed oxide is called phosphosilicate glass (PSG). The PSG has a softening point different from that of phosphorus oxide and a diffusion constant which varies depending on the concentration of phosphorus oxide present. The mixed oxide acts as a diffusion source for the germanium wafer, wherein the phosphorous oxide diffuses along the interface between the PSG and the germanium wafer during the diffusion process, in which case it is reacted with the germanium at the surface of the wafer. Reduction to phosphorus (silicothermally). The phosphorus formed in this way has a higher order of solubility in the crucible than in the glass substrate in which it has been formed and is therefore preferentially dissolved in the crucible due to the extremely high segregation coefficient. After dissolution, phosphorus diffuses into the crucible with a concentration gradient into the volume of the crucible.

在此擴散過程中，於典型的為10²¹個原子/cm²之表面濃度及區域中為10¹⁶個原子/cm²之基區摻雜之間形成數量級為10⁵之濃度梯度。典型的擴散深度為250至500nm且取決於例如在約880℃下所選的擴散溫度及晶圓在經強加熱之氛圍中之暴露總持續時間(加熱、塗佈期、驅入期及冷卻)而改變。在塗佈期間，PSG層形成，其通常具有40至60nm之層厚度。以PSG塗佈晶圓，在此期間亦已經發生擴散進入矽體積中，接著係驅入期。此可從塗佈期去耦，但在實務中一般以時間計直接耦合至塗層及因此通常亦在相同溫度下進行。以使得抑制進一步提供磷醯氯之方式調整本文中氣體混合物之組成。 In this diffusion process, a concentration gradient of the order of 10 ⁵ is formed between the surface concentration of typically 10 ²¹ atoms/cm ² and the doping of 10 ¹⁶ atoms/cm ^{2 in} the region. Typical diffusion depths are from 250 to 500 nm and depend on, for example, the diffusion temperature selected at about 880 ° C and the total duration of exposure of the wafer in a strongly heated atmosphere (heating, coating period, flooding period, and cooling) And change. During coating, a PSG layer is formed which typically has a layer thickness of 40 to 60 nm. The wafer is coated with PSG, during which time diffusion has also occurred into the crucible volume, followed by a drive-in period. This can be decoupled from the coating period, but is generally directly coupled to the coating in terms of time in practice and is therefore typically also carried out at the same temperature. The composition of the gas mixture herein is adjusted in such a manner as to inhibit further supply of phosphonium chloride.

在驅入期間，矽表面進一步被存於氣體混合物中之氧氧化，引起在實際摻雜源、高度富含氧化磷之PSG及矽晶圓之間產生同樣包含氧化磷之耗乏氧化磷之二氧化矽層。這一層之生長就來自來源(PSG)之摻雜劑的質量流量而言變的非常地快，此乃因氧化物生長藉由晶圓本身之高表面摻雜加速(以一至兩個數量級加速)。此可使得摻雜源之耗乏或分離以特定方式達成，隨著氧化磷擴散之滲透受到材料流量影響，該材料流量取決於溫度及因此取決於擴散係數而改變。依此方式，矽之摻雜可控制在特定限度內。典型的由塗佈期及驅入期組成之擴散持續時間為例如25分鐘。於此處理之後，使管狀爐自動冷卻，及可在介於600℃與700℃之間之溫度下自製程管移出晶圓。 During the drive-in period, the surface of the crucible is further oxidized by oxygen stored in the gas mixture, causing the consumption of phosphorus oxide which also contains phosphorus oxide between the actual doping source, the PSG rich in phosphorus oxide and the germanium wafer. Oxide layer. The growth of this layer is very fast in terms of the mass flow rate of the source (PSG) dopant, since the oxide growth is accelerated by the high surface doping of the wafer itself (accelerated by one to two orders of magnitude) . This can result in the depletion or separation of the dopant source in a particular manner, as the diffusion of the phosphorus oxide diffusion is affected by the material flow, which varies depending on the temperature and therefore on the diffusion coefficient. In this way, the doping of the crucible can be controlled within certain limits. A typical diffusion duration consisting of a coating period and a flooding period is, for example, 25 minutes. After this treatment, the tubular furnace is automatically cooled, and the wafer can be removed from the wafer at a temperature between 600 ° C and 700 ° C.

就呈n型基區摻雜形式之晶圓之硼摻雜而言，採用不同的方法，本文中該不同方法將不作單獨說明。此等情況中之摻雜例如以三氯化硼或三溴化硼進行。取決於用於摻雜之氣體氛圍之組成之選擇，可觀察到所謂的硼表層在晶圓上形成。該硼表層取決於各種影響因素而改變，更確切地說在關鍵程度上取決於上文所述之摻雜氛圍、溫度、摻雜持續時間、來源濃度及耦合(或線性組合)參數。 For boron doping of wafers in the form of n-type base doping, different methods are used, and the different methods herein will not be separately described. Doping in such cases is carried out, for example, with boron trichloride or boron tribromide. Depending on the choice of composition of the gas atmosphere used for doping, a so-called boron skin layer can be observed to form on the wafer. The boron skin layer varies depending on various influencing factors, more precisely on a critical extent depending on the doping atmosphere, temperature, doping duration, source concentration and coupling (or linear combination) parameters described above.

在此等擴散製程中，毋庸贅言，若基板先前未經過對應之預處理(例如，其藉由擴散抑制及/或擴散壓制層及材料結構化)，則所使用的晶圓會不包含任何的較佳擴散及摻雜之區域(除了彼等藉由非均質氣流及所產生的非均質組合物之氣泡形成者之外)。 In such diffusion processes, it goes without saying that if the substrate has not been previously pretreated (for example, by diffusion suppression and/or diffusion of the pressed layer and material structure), the wafer used will not contain any Preferred regions for diffusion and doping (except for those formed by the heterogeneous gas stream and the bubble former of the resulting heterogeneous composition).

為完整起見，本文亦應指出亦存在於製造基於矽之晶型太陽能電池中在不同程度上成立之其他擴散及摻雜技術。因此，可提及.離子植入，.通過混合氧化物之氣相沉積，諸如，例如，PSG及BSG(硼矽酸鹽玻璃)之氣相沉積，借助於APCVD、PECVD、MOCVD及LPCVD製程促進之摻雜，.混合氧化物及/或陶瓷材料及硬材料(例如氮化硼)之共濺鍍，.自實心摻雜劑源(例如氧化硼及氮化硼)開始之純熱氣相沉積，.硼濺鍍至矽表面上及其熱驅入至矽晶體中，.自不同組合物諸如(例如)Al₂O₃、SiO_xN_y之介電鈍化層之雷射摻雜，其中後者包含呈經混合之P₂O₅及B₂O₃之形式之摻雜劑，.及具有摻雜作用之液體或膏劑之液相沉積。 For the sake of completeness, it should also be noted that other diffusion and doping techniques that are also present to varying degrees in the fabrication of germanium-based crystalline solar cells are also noted. Thus, mention may be made of ion implantation, by vapor deposition of mixed oxides, such as, for example, vapor deposition of PSG and BSG (boron silicate glass), by means of APCVD, PECVD, MOCVD and LPCVD processes. Doping, co-sputtering of mixed oxides and/or ceramic materials and hard materials such as boron nitride, pure thermal vapor deposition starting from solid dopant sources such as boron oxide and boron nitride, Boron is sputtered onto the surface of the crucible and its thermal drive into the germanium crystal, from the laser doping of different compositions such as, for example, a dielectric passivation layer of Al ₂ O ₃ , SiO _x N _y , wherein the latter comprises A dopant in the form of a mixed P ₂ O ₅ and B ₂ O ₃ , and a liquid phase deposition of a doping liquid or paste.

後者通常用於所謂的線上摻雜，其中對應之膏劑及印墨係通過適宜方法施覆至待摻雜晶圓側。在施覆後亦或甚至在施覆期間，藉由溫度及/或真空處理移除存於用於摻雜之組合物中之溶劑。此使得實際摻雜劑留在晶圓表面後。可使用的液體摻雜源為(例如)磷酸或硼酸之稀溶液亦及基於溶膠-凝膠之系統亦或聚合borazil化合物之溶液。對應之摻雜膏劑之實質上唯一特徵係使用額外增稠聚合物，且包含呈適宜形式之摻雜劑。通常在自上述摻雜介質蒸發溶劑後進行高溫下處理，於高溫下熱處理期間，除了為調配時所必需的添加劑之外之非所欲且具干擾性之添加劑係「燒除」及/或熱解。溶劑之移除及燒盡可(但無需)同時發生。經塗佈之基板隨後通常通過介於800℃與1000℃之間之溫度之直流爐，其中該等溫度可相較於管狀爐中之氣相擴散略微提高以縮短通過時間。直流爐中主要的氣體氛圍可根據摻雜之要求有所不同及可由乾燥氮氣、乾燥空氣、乾燥氧氣與乾燥氮氣之混合物組成，且/或係取決於待通過的爐、一種或其他上述氣體氛圍之區之設計而改變。可設想其他氣體混合物，但目前在工業上並非極度重要。線上擴散之特徵為摻雜劑之塗佈及驅入可原則上彼此去耦合發生。 The latter is commonly used for so-called in-line doping, in which the corresponding paste and ink are applied to the side of the wafer to be doped by a suitable method. The solvent present in the composition for doping is removed by temperature and/or vacuum treatment after application or even during application. This leaves the actual dopant behind the wafer surface. Liquid doping sources that can be used are, for example, phosphoric acid or boric acid The dilute solution is also a solution based on a sol-gel system or a polymeric borazil compound. A substantially unique feature of the corresponding doped paste is the use of an additional thickening polymer and comprising a dopant in a suitable form. Usually, after evaporating the solvent from the above doping medium, the treatment is carried out at a high temperature, and during the heat treatment at a high temperature, the undesired and interfering additives other than the additives necessary for blending are "burned out" and/or heat. solution. Solvent removal and burnout can occur (but need not) at the same time. The coated substrate is then typically passed through a direct current furnace at a temperature between 800 ° C and 1000 ° C, wherein the temperatures can be slightly increased compared to the gas phase diffusion in the tubular furnace to reduce the passage time. The main gas atmosphere in the DC furnace may vary depending on the doping requirements and may consist of a mixture of dry nitrogen, dry air, dry oxygen and dry nitrogen, and/or depending on the furnace to be passed, one or the other gas atmosphere The design of the district changes. Other gas mixtures are conceivable, but are currently not extremely important in the industry. The feature of on-line diffusion is that the coating and driving of the dopants can occur in principle with each other.

3)移除摻雜劑源及視需要之邊緣隔離 3) Remove dopant source and optionally edge isolation

於摻雜後呈現的晶圓之兩側在表面兩側上塗佈或多或少的玻璃。或多或少在此情況中係指可在摻雜製程中施用的變化：雙側擴散與藉由兩晶圓在所使用的製程皿(process boats)之一種位置中之背對背配置促進之實質上單側擴散相比。後種變體主要實現單側摻雜，但並不完全抑制背部上之擴散。在兩種情況中，當前技術狀態係通過在稀氫氟酸中蝕刻自表面移除摻雜後存在的玻璃。對此，一方面分批將晶圓再加載至濕式製程皿中且藉助後者浸漬於稀氫氟酸溶液(通常2%至5%)中，並留在其中直到表面已完全無玻璃、或代表必要蝕刻持續時間及藉由機器之製程自動化之總和參數之製程週期持續時間已期滿。可例如由藉由稀氫氟酸水溶液完全去濕矽晶圓表面來實現完全移除玻璃。在此等製程條件(例如使用2%氫氟酸溶液)下於室溫在210秒內來實現完全移除PSG。對應之BSG之蝕刻較慢及需要較長的製程時間及所使用的氫氟酸亦可能需要較高濃度。於蝕刻後，用水沖洗晶圓。 Both sides of the wafer presented after doping are coated with more or less glass on both sides of the surface. More or less in this case is meant a change that can be applied during the doping process: bilateral diffusion and the back-to-back configuration facilitated by the two wafers in one location of the process boats used. Compared to single-sided diffusion. The latter variant primarily achieves one-sided doping, but does not completely inhibit diffusion on the back. In both cases, the current state of the art is to remove the glass present after doping by etching in dilute hydrofluoric acid from the surface. In this regard, on the one hand, the wafer is reloaded into the wet process vessel in batches and immersed in a dilute hydrofluoric acid solution (usually 2% to 5%) by means of the latter, and remains therein until the surface is completely free of glass, or The process cycle duration representing the necessary etch duration and the summation parameters of the process automation by the machine has expired. Complete removal of the glass can be achieved, for example, by completely dehumidifying the surface of the wafer with a dilute aqueous solution of hydrofluoric acid. Complete removal of the PSG is achieved at room temperature in 210 seconds under such process conditions (eg, using a 2% hydrofluoric acid solution). When the corresponding BSG is etched slowly and requires a long process Higher concentrations may also be required between the hydrofluoric acid used and the hydrofluoric acid used. After etching, the wafer is rinsed with water.

另一方面，亦可在水平操作製程中進行晶圓表面上玻璃之蝕刻，其中該等晶圓係以恆定流引入至晶圓水平通過對應之製程槽(線上機器)之蝕刻器中。在此情況中，晶圓於輥上傳送通過製程槽及存於其中的蝕刻溶液中任一者，或蝕刻介質藉由輥施覆輸送至晶圓表面上。蝕刻PSG期間晶圓之典型滯留時間為約90秒，及所使用的氫氟酸相較於分批製程情況具稍更高濃度以補償因蝕刻速率增加而縮短的滯留時間。氫氟酸之濃度通常為5%。槽溫度可視需要另外比室溫略高(高於25℃低於50℃)。 Alternatively, the etching of the glass on the wafer surface can be performed in a horizontal operation process in which the wafers are introduced in a constant flow into the etcher of the wafer level through the corresponding process slot (on-line machine). In this case, the wafer is transferred over the roll through the process slot and any of the etching solutions present therein, or the etched media is applied to the wafer surface by roll coating. The typical residence time of the wafer during etching of the PSG is about 90 seconds, and the hydrofluoric acid used has a slightly higher concentration than the batch process to compensate for the reduced residence time due to the increased etch rate. The concentration of hydrofluoric acid is usually 5%. The bath temperature may optionally be slightly higher than room temperature (above 25 ° C below 50 ° C).

在最後所概述的製程中，已實現在相同時間連續進行所謂的邊緣隔離，產生出略有所改變的製程流： In the last outlined process, so-called edge isolation has been achieved continuously at the same time, resulting in a slightly changed process flow:

邊緣隔離→玻璃蝕刻。 Edge isolation → glass etching.

邊緣隔離為製程中由雙側擴散(亦在刻意單側背對背擴散情況下)之系統固有特徵引起之技術必要性。大面積寄生性p-n接面存在於太陽能電池之(稍後)背上，其出於製程工程原因而部分地(但非完全地)在後來的處理中移除。此舉的結果是，太陽能電池之前側及背側將已通過寄生性及殘留之p-n接面(穿隧接觸)短路，此降低隨後的太陽能電池之轉換效率。就移除此接面而言，晶圓於一側上通過由硝酸及氫氟酸組成之蝕刻溶液。蝕刻溶液可包含例如硫酸或磷酸作為第二組分。或者，蝕刻溶液通過輥輸送(傳送)至晶圓之背側上。約1μm矽(包括存於待處理的表面上之玻璃層)通常藉由在此製程中於介於4℃與8℃之間之溫度下蝕刻移除。在此製程中，仍存於晶圓之相對側上之玻璃層充作遮罩，此可提供特定保護以防過度蝕刻至該側上。隨後藉助已描述之玻璃蝕刻移除此玻璃層。 Edge isolation is a technical necessity caused by the inherent characteristics of the system that is diffused by both sides (also in the case of deliberate one-sided back-to-back diffusion). A large area of parasitic p-n junctions is present on the (later) back of the solar cell, which is partially (but not completely) removed for later processing for process engineering reasons. As a result of this, the front side and the back side of the solar cell will have been short-circuited by parasitic and residual p-n junctions (tunneling contacts), which reduces the conversion efficiency of subsequent solar cells. To remove this junction, the wafer passes through an etching solution consisting of nitric acid and hydrofluoric acid on one side. The etching solution may contain, for example, sulfuric acid or phosphoric acid as the second component. Alternatively, the etching solution is transported (transferred) through a roller onto the back side of the wafer. Approximately 1 μm (including the glass layer deposited on the surface to be treated) is typically removed by etching in a temperature between 4 ° C and 8 ° C in this process. In this process, the glass layer still on the opposite side of the wafer acts as a mask, which provides specific protection against over-etching onto the side. This glass layer is then removed by means of the already described glass etching.

此外，亦可藉助電漿蝕刻製程進行邊緣隔離。接著，一般在玻璃蝕刻之前進行此電漿蝕刻。對此，以一個晶圓在另一晶圓頂部方式堆疊複數個晶圓，及將外邊緣暴露於電漿。用氟化氣體，例如四氟甲烷饋送電漿。於此等氣體之電漿分解時產生之反應性物質蝕刻晶圓之邊緣。一般而言，進行電漿蝕刻，接著進行玻璃蝕刻。 In addition, edge isolation can also be performed by means of a plasma etching process. Then, generally in glass This plasma etching is performed before the glass etching. In this regard, a plurality of wafers are stacked on one wafer at the top of the other wafer, and the outer edges are exposed to the plasma. The plasma is fed with a fluorinated gas such as tetrafluoromethane. The reactive material generated during the decomposition of the plasma of the gas etches the edge of the wafer. In general, plasma etching is performed followed by glass etching.

4)以抗反射層塗佈前表面 4) Coating the front surface with an anti-reflection layer

於蝕刻玻璃及視需要之邊緣隔離後，以抗反射層塗佈隨後的太陽能電池之前表面，該抗反射塗層通常係由非晶型且富含氫之氮化矽組成。可設想替代性抗反射塗層。可行的塗層可由二氧化鈦、氟化鎂、二氧化錫及/或對應之二氧化矽及氮化矽之堆疊層組成。然而，具有不同組成之抗反射塗層亦係技術上可行的。以上述氮化矽塗佈晶圓表面基本上實現兩種功能：一方面，層由於許多經併入之正電荷而產生電場，此可維持矽中的電荷載子遠離表面且可顯著降低此等電荷載子在矽表面處之重組速率(場效鈍化)，另一方面，此層取決於其光學參數，諸如，例如折射率及層厚度而產生減反射性質，此造成更多光可耦合至隨後的太陽能電池中。這兩種效應可提高太陽能電池之轉換效率。目前所使用的層之典型性質為：在僅使用上述氮化矽時為約80nm之層厚度，該氮化矽具有約2.05之折射率。抗反射之降低最明顯出現在600nm之光波長區。本文中定向及無向之反射展現初始入射光(垂直入射至與矽晶圓垂直之表面)之約1%至3%之值。 After etching the etched glass and optionally the edges, the surface of the subsequent solar cell is coated with an anti-reflective coating, which is typically composed of amorphous and hydrogen-rich tantalum nitride. Alternative anti-reflective coatings are contemplated. Possible coatings may consist of a stack of titanium dioxide, magnesium fluoride, tin dioxide and/or corresponding tantalum dioxide and tantalum nitride. However, antireflective coatings having different compositions are also technically feasible. Coating the wafer surface with the above-described tantalum nitride substantially accomplishes two functions: on the one hand, the layer generates an electric field due to a plurality of incorporated positive charges, which maintains the charge carriers in the crucible away from the surface and can significantly reduce such The rate of recombination of charge carriers at the surface of the crucible (field effect passivation), on the other hand, this layer produces anti-reflective properties depending on its optical parameters, such as, for example, refractive index and layer thickness, which causes more light to be coupled to Subsequent solar cells. These two effects can improve the conversion efficiency of the solar cell. A typical property of the layer currently used is a layer thickness of about 80 nm when only the above-mentioned tantalum nitride is used, and the tantalum nitride has a refractive index of about 2.05. The reduction in anti-reflection most clearly occurs in the wavelength region of light at 600 nm. The orientation and undirected reflections herein exhibit values from about 1% to 3% of the initial incident light (perpendicular to the surface perpendicular to the germanium wafer).

上述氮化矽層目前一般通過直接PECVD製程沉積於表面上。對此，在氬氣氛圍中點燃引入矽烷及氨的電漿。矽烷與氨在電漿中通過離子及自由基反應反應以提供氮化矽及在相同時間沉積於晶圓表面上。可例如通過反應物之個別氣流調整並控制層之性質。亦可用用作載體氣體之氫氣及/或僅反應物進行上述氮化矽層之沉積。典型沉積溫度在介於300℃與400℃之間之範圍內。替代性沉積方法可為例如LPCVD及/或濺鍍。 The above tantalum nitride layer is currently deposited on the surface by a direct PECVD process. In this regard, a plasma in which decane and ammonia are introduced is ignited in an argon atmosphere. The decane and ammonia are reacted by ions and radicals in the plasma to provide tantalum nitride and deposited on the surface of the wafer at the same time. The properties of the layer can be adjusted and controlled, for example, by individual gas flows of the reactants. The deposition of the above tantalum nitride layer may also be carried out using hydrogen gas and/or only a reactant as a carrier gas. Typical deposition temperatures range between 300 ° C and 400 ° C. Alternative deposition methods can be, for example, LPCVD and/or sputtering.

5)製造前表面電極柵 5) Manufacturing the front surface electrode grid

於沉積抗反射層後，在塗佈氮化矽之晶圓表面上界定前表面電極。在工業實務中，已確立藉助網版印刷法使用金屬燒結膏來製造電極。然而，此僅為製造所需金屬觸點之許多不同可能性之一。 After depositing the antireflective layer, the front surface electrode is defined on the surface of the wafer coated with tantalum nitride. In industrial practice, it has been established to fabricate electrodes using a metal frit paste by means of screen printing. However, this is only one of many different possibilities for making the required metal contacts.

在網版印刷金屬化中，一般使用高度富含銀顆粒(銀含量大於或等於80%)之膏。剩餘組分總和源自於為調配膏時所必需的流變學助劑，諸如(例如)溶劑、黏合劑及增稠劑。另外，銀膏包含特定玻璃料混合物(通常氧化物及基於二氧化矽的混合氧化物)、硼矽酸鹽玻璃亦及氧化鉛及/或氧化鉍。玻璃料基本上實現兩種功能：一方面其充作晶圓表面與大多數待燒結的銀顆粒之間之黏著促進劑，另一方面其造成穿透氮化矽頂層以促進與下層矽直接歐姆接觸。氮化矽之穿透係通過蝕刻製程且隨後溶於玻璃料基底中的銀擴散至矽表面中，藉此實現歐姆接觸形成而發生。在實務中，銀膏通過網版印刷及隨後在約200℃至300℃之溫度下乾燥數分鐘而沉積於晶圓表面上。為完整起見，應提及的是，亦在工業上使用雙重印刷製程，此使得第二電極柵以準確對齊印刷至在第一印刷步驟中產生之電極柵上。銀金屬化之厚度因此增加，此可對電極柵之導電性具有正影響。在此乾燥期間，存於膏中之溶劑自膏驅出。經印刷之晶圓於隨後通過直流爐。此類型之爐一般具有複數個可活化且彼此獨立控制溫度之加熱區。在鈍化直流爐期間，將晶圓加熱至高達約950℃之溫度。然而，個別晶圓一般僅經歷該峰值溫度數秒。在直流步驟之剩餘時間期間，晶圓具有600℃至800℃之溫度。在此等溫度下，存於銀膏中之有機伴隨物質(諸如，例如黏合劑)燒盡，及氮化矽層之蝕刻開始。在當時峰值溫度之短的時間間隔期間，發生與矽形成觸點。於隨後使該等晶圓冷卻。 In screen printing metallization, pastes that are highly enriched in silver particles (with a silver content greater than or equal to 80%) are generally used. The sum of the remaining components is derived from the rheology aids necessary for formulating the paste, such as, for example, solvents, binders, and thickeners. In addition, the silver paste comprises a specific glass frit mixture (usually an oxide and a cerium oxide-based mixed oxide), a borosilicate glass, and lead oxide and/or cerium oxide. The glass frit basically achieves two functions: on the one hand, it acts as an adhesion promoter between the wafer surface and most of the silver particles to be sintered, and on the other hand it causes penetration of the top layer of the tantalum nitride to promote direct ohmic with the underlying layer. contact. The penetration of tantalum nitride occurs by an etching process and then the silver dissolved in the frit substrate diffuses into the surface of the crucible, thereby achieving ohmic contact formation. In practice, the silver paste is deposited on the wafer surface by screen printing and subsequent drying at a temperature of about 200 ° C to 300 ° C for a few minutes. For the sake of completeness, it should be mentioned that a dual printing process is also used in the industry, which allows the second electrode grid to be printed in an exact alignment onto the electrode grid produced in the first printing step. The thickness of the silver metallization is thus increased, which has a positive influence on the conductivity of the electrode grid. During this drying, the solvent stored in the paste is driven out of the paste. The printed wafer is then passed through a DC furnace. This type of furnace typically has a plurality of heating zones that are activatable and independently control the temperature. During passivation of the DC furnace, the wafer is heated to a temperature of up to about 950 °C. However, individual wafers typically only experience this peak temperature for a few seconds. The wafer has a temperature of 600 ° C to 800 ° C during the remainder of the DC step. At these temperatures, the organic concomitant material (such as, for example, a binder) stored in the silver paste is burned out, and the etching of the tantalum nitride layer begins. During the short time interval of the peak temperature at that time, a contact is formed with the crucible. The wafers are subsequently cooled.

簡單依此方式概述之觸點形成製程通常與兩種其餘觸點形成(請參閱章節6及7)同時進行，此乃術語共燒製製程亦用於此情況中的原因。 A simple contact forming process outlined in this manner is usually performed simultaneously with the formation of two remaining contacts (see Sections 6 and 7), which is the term co-firing process also used in this case. because.

前表面電極柵本身由具有通常60μm至140μm之寬度之薄指狀部(就發射體薄片電阻>50Ω/sqr而言，典型數量多於或等於68個)亦及具有在1.2mm至2.2mm範圍內之寬度(取決於其數量，通常兩至三個)之匯流條組成。經印刷之銀元件之典型高度一般在10μm與25μm之間。長寬比很少會大於0.3，但可通過選擇替代性且/或適合之金屬化製程顯著增加。可提及的替代性金屬化製程為金屬膏之施配。適合之金屬化製程係基於兩次連續的視需要用兩種不同組成之金屬膏之網版印刷製程(雙重印刷或在印刷上印刷(print-on-print))。特別就最後所提及的製程而言，可使用所謂的浮動匯流條，其確保電流自聚集電荷載子之指狀部消散，但其實際上並非與矽晶體本身直接歐姆接觸。 The front surface electrode grid itself is made up of thin fingers having a width of typically 60 μm to 140 μm (typically more than or equal to 68 for emitter sheet resistance >50 Ω/sqr) and having a range of 1.2 mm to 2.2 mm. A bus bar consisting of the width (depending on its number, usually two to three). Typical heights of printed silver components are typically between 10 μm and 25 μm. The aspect ratio will rarely be greater than 0.3, but can be significantly increased by selecting alternative and/or suitable metallization processes. Alternative metallization processes that may be mentioned are the application of metal pastes. A suitable metallization process is based on two consecutive screen printing processes (double-printing or print-on-print) of two different metal pastes as needed. In particular for the last mentioned process, a so-called floating bus bar can be used which ensures that the current dissipates from the fingers of the collector charge, but which is not in direct ohmic contact with the germanium crystal itself.

6)製造背表面匯流條 6) Manufacturing the back surface bus bar

一般亦通過網版印刷製程施加及界定背表面匯流條。對此，使用與用於前表面金屬化之銀膏類似的銀膏。此種膏具有相似的組成，但包含銀與鋁之合金，其中鋁的比例通常佔2%。此外，此種膏包含較低的玻璃料含量。一般兩個單元之匯流條通過網版印刷4mm之典型寬度而印刷至晶圓背側上且如已在章節5中描述壓實並燒結。 The back surface bus bar is also typically applied and defined by a screen printing process. For this, a silver paste similar to the silver paste used for front surface metallization is used. This paste has a similar composition but contains an alloy of silver and aluminum, with aluminum typically accounting for 2%. In addition, such pastes contain a lower frit content. Typically, the busbars of the two cells are printed onto the back side of the wafer by a typical width of 4 mm screen printing and compacted and sintered as described in Section 5.

7)製造背表面電極 7) Manufacturing the back surface electrode

在匯流條之印刷後界定背表面電極。電極材料由鋁組成，此乃含鋁膏通過網版印刷且具有用於界定電極之小於1mm之邊緣分隔印刷至晶圓背側之其餘自由區的原因。該膏係由大於或等於80%鋁組成。剩餘組分為彼等已在章節5下所提及者(諸如，例如，溶劑、黏合劑等)。鋁膏係在共燒製期間藉由鋁顆粒在升溫期間開始熔化及來自晶圓之矽溶解於熔融鋁中而黏合至晶圓。熔融混合物作用為摻雜劑源且釋放鋁至矽(溶解度限值：0.016原子百分比)，其中因此種驅入而造成矽係經p⁺摻雜。在使晶圓冷卻期間，在577℃固化且具有具有0.12 莫耳分率Si之組成之鋁與矽之低共熔混合物尤其沉積於晶圓表面上。 The back surface electrode is defined after printing of the bus bar. The electrode material consists of aluminum, which is why the aluminum-containing paste is screen printed and has the edges of less than 1 mm defining the electrodes separating the remaining free areas printed onto the back side of the wafer. The paste consists of greater than or equal to 80% aluminum. The remaining components are those which have been mentioned under Section 5 (such as, for example, solvents, binders, etc.). The aluminum paste is bonded to the wafer during co-firing by the aluminum particles beginning to melt during the temperature rise and the enthalpy from the wafer being dissolved in the molten aluminum. The molten mixture acts as a dopant source and releases aluminum to bismuth (solubility limit: 0.016 atomic percent), wherein the species are driven to cause the lanthanide to be p ⁺ doped. During the cooling of the wafer, a eutectic mixture of aluminum and tantalum cured at 577 ° C and having a composition of 0.12 mole fraction Si is deposited, inter alia, on the wafer surface.

由於鋁驅入矽中，作為一種鏡(「電鏡(electric mirror)」)作用於矽中部分游離電荷載子上之經高度摻雜之p型層形成於晶圓背側上。此等電荷載子無法克服此種電位壁及因此極有效地遠離背晶圓表面，此點因此由電荷載子在此表面處之重組率總體降低獲得證實。此電位壁一般稱為「背表面場」。 Since the aluminum is driven into the crucible, a highly doped p-type layer acting as a mirror ("electric mirror") on a portion of the free charge carriers in the crucible is formed on the back side of the wafer. These charge carriers are unable to overcome such potential walls and are therefore extremely effective away from the back wafer surface, as evidenced by the overall reduction in the recombination rate of charge carriers at this surface. This potential wall is generally referred to as the "back surface field."

已在章節5、6及7描述之製程步驟之順序可對應於本段所概述之順序。然而，此不是絕對必需的。熟悉此項技術者明瞭原則上可以任何可設想組合進行所概述製程步驟之順序。 The sequence of process steps already described in Sections 5, 6 and 7 may correspond to the order outlined in this paragraph. However, this is not absolutely necessary. It will be apparent to those skilled in the art that the sequence of process steps outlined can be performed in any conceivable combination.

8)視需要之邊緣隔離 8) Edge isolation as needed

若尚未如點3下方所述進行邊緣隔離，則通常在共燒製後藉助雷射法進行此種邊緣隔離。對此，將雷射束導引於太陽能電池之前側，及前表面p-n接面藉助以此雷射束耦合之能量而分割。由於雷射作用而在此產生具有深達15μm深度之切割溝槽。矽係自經處理之部位通過剝蝕機制移除或自雷射溝槽除去。此雷射溝槽通常具有30μm至60μm之寬度且離太陽能電池之邊緣約200μm。 If edge separation has not been performed as described below in point 3, such edge isolation is typically performed by means of a laser after co-firing. In this regard, the laser beam is directed to the front side of the solar cell, and the front surface p-n junction is divided by the energy coupled by the laser beam. Due to the laser action, a cutting groove having a depth of up to 15 μm is produced here. The lanthanide is removed from the treated part by an ablation mechanism or removed from the laser trench. This laser trench typically has a width of from 30 μm to 60 μm and is about 200 μm from the edge of the solar cell.

於製造後，太陽能電池根據其個別性能進行表徵並歸類為個別性能類別。 After fabrication, solar cells are characterized according to their individual properties and classified into individual performance categories.

熟悉此項技術者明瞭具有n型亦及p型兩種基底材料之太陽能電池架構。此等太陽能電池類型包括 Those skilled in the art will recognize solar cell architectures having both n-type and p-type substrate materials. These types of solar cells include

.PERC太陽能電池 .PERC solar cell

.PERT太陽能電池 .PERT solar cell

.PERL太陽能電池 .PERL solar cell

.MWT太陽能電池 .MWT solar cell

.衍生自其之MWT-PERC、MWT-PERT及MWT-PERL太陽能電池 . MWT-PERC, MWT-PERT and MWT-PERL solar cells derived from them

.具有均勻且選擇性之背表面場之雙面太陽能電池 Double-sided solar cell with uniform and selective back surface field

.背表面接觸電池 . Back surface contact battery

.具有叉指形觸點之背表面接觸電池。 The back surface with the interdigitated contacts contacts the battery.

選擇替代性摻雜技術作為已於導論中描述之氣相摻雜之替代一般亦不能解決在矽基板上產生出具有局部不同摻雜之區域的問題。此處可提及的替代性技術為經摻雜玻璃或非晶型經混合氧化物之通過PECVD及APCVD製程之沉積。可輕易地自此等玻璃實現位於此等玻璃下方之矽之熱引起之摻雜。然而，為了產生具有局部不同摻雜之區域，必須通過遮罩製程蝕刻此等玻璃以自此等玻璃製造對應之結構。或者，可在沉積玻璃之前沉積結構化擴散障壁於矽晶圓上以藉此界定待沉積的區域。然而，此製程中在各情況中僅可實現摻雜之一種極性(n或p)係不利的。比摻雜源或任何擴散障壁之結構化稍微簡單的是自事先沉積於晶圓表面上之摻雜劑源經直接雷射束支持將摻雜劑驅入。此製程可實現意欲節省之昂貴結構化步驟。然而，無法補償可能需要於相同表面上在相同時間同時摻雜兩種極性(共擴散)的缺點，此乃因此製程亦基於僅於隨後活化以釋放摻雜劑之預沉積摻雜劑源。此種自該等來源之(後)摻雜的一個缺點為基板之不可避免的雷射損傷：雷射束必須藉由吸收輻射而轉化成熱。由於習知摻雜劑源由矽之混合氧化物及待驅入的摻雜劑(亦即，由就硼而言氧化硼)組成，故此等混合氧化物之光學性質因此與氧化矽之光學性質非常相似。此等玻璃(混合氧化物)因此對相關波長範圍內輻射具有極低吸收係數。出於此原因，使用位於光學透明玻璃下方之矽作為吸收源。在一些情況中於此處使矽升溫直到其熔化，及因此使位於其上方之玻璃升溫。此有利於擴散摻雜劑-及如此做將預期在正常擴散溫度下快多倍，因此發生矽之極短擴散時間(短於1秒)。待在吸收雷射輻射後由於強消散熱至矽之其餘非照射體積中而使矽相對快速地再次冷卻且外延固化於非熔融材料上。然而，整體製程事實上伴隨形成雷射輻射引起之缺陷，此可歸因於不完全外延固化及因此形成晶體缺陷。此可例如歸因於由於製程之衝擊樣進展造成之空位及瑕疵之位錯及形成。雷射束支持之擴散的另一缺點為在待快速地摻雜相對大區域之情況下相對無效，此乃因在點-柵製程中雷射系統掃描表面。此缺點在待摻雜的狹窄區域情況中自然地具有較小的影響。然而，雷射摻雜需要連續沉積可後處理之玻璃。 The choice of alternative doping techniques as an alternative to gas phase doping as described in the introduction generally does not solve the problem of creating regions of locally different doping on the germanium substrate. An alternative technique that may be mentioned herein is the deposition of a doped glass or amorphous mixed oxide by PECVD and APCVD processes. The doping of the heat caused by the heat of the glass under such glass can be easily achieved from such a glass. However, in order to create regions with locally different doping, the glasses must be etched by a mask process to fabricate the corresponding structures from such glasses. Alternatively, a structured diffusion barrier can be deposited on the germanium wafer prior to depositing the glass to thereby define the area to be deposited. However, it is disadvantageous in this process that only one polarity (n or p) of doping can be achieved in each case. The structuring of the dopant source or any diffusion barrier is somewhat simple in that the dopant source is driven from the dopant source previously deposited on the wafer surface via direct laser beam support. This process enables an expensive structuring step that is intended to be saved. However, the inability to compensate for the possibility of simultaneously doping two polarities (co-diffusion) at the same time on the same surface cannot be compensated for, so the process is therefore based on a pre-deposited dopant source that is only activated subsequently to release the dopant. One disadvantage of such (post) doping from such sources is the inevitable laser damage of the substrate: the laser beam must be converted to heat by absorbing radiation. Since the conventional dopant source consists of a mixed oxide of cerium and a dopant to be driven (ie, boron oxide in terms of boron), the optical properties of the mixed oxide are thus related to the optical properties of cerium oxide. very similar. These glasses (mixed oxides) therefore have a very low absorption coefficient for radiation in the relevant wavelength range. For this reason, a crucible located below the optically transparent glass is used as the absorption source. In some cases, the crucible is heated here until it melts, and thus the glass above it is warmed. This facilitates the diffusion of the dopant - and doing so would be expected to be many times faster at normal diffusion temperatures, thus causing extremely short diffusion times (less than 1 second). After absorption of the laser radiation, the ruthenium is relatively quickly re-cooled and epitaxially solidified on the non-molten material due to the strong dissipation of heat to the remaining non-irradiation volume of the crucible. However, the overall process is in fact accompanied by the formation of defects caused by laser radiation, which can Due to incomplete epitaxial curing and thus formation of crystal defects. This can be attributed, for example, to the vacancies and formation of vacancies and defects due to the progress of the impact of the process. Another disadvantage of the spread of the laser beam support is that it is relatively ineffective in the case of rapidly doping a relatively large area, as the laser system scans the surface during the dot-gate process. This disadvantage naturally has a small effect in the case of a narrow region to be doped. However, laser doping requires continuous deposition of post-processable glass.

本發明之目標The object of the invention

本發明之目標包括提供一種用於製造更有效率之改善自入射於太陽能電池上之光及藉此在太陽能電池中產生之電荷載子電流生產率之太陽能電池之方法及組合物。就此而言，期望廉價之結構化，可達成相比目前在技術上主導的摻雜製程改良之競爭性。 It is an object of the present invention to provide a method and composition for making a more efficient solar cell that improves light from incident on a solar cell and thereby generates charge current in the solar cell. In this regard, it is desirable to have a cheaper structuring that achieves competability over current technologically dominant doping process improvements.

本發明係關於一種新穎的直接摻雜矽基板之方法，其中a)以整個表面或選擇性地將適合用作溶膠-凝膠以用於形成氧化物層且包含至少一種選自群組硼、鎵、矽、鍺、鋅、錫、磷、鈦、鋯、釔、鎳、鈷、鐵、鈰、鈮、砷及鉛之摻雜元素之摻雜膏印刷至基板表面上，並乾燥，b)視需要用相同或不同組成之摻雜膏重複此步驟，及c)視需要藉由在750至1100℃範圍內的溫度下溫度處理進行藉由擴散之摻雜，及d)藉由雷射照射進行基板之摻雜，及e)視需要藉由管狀爐步驟或線上擴散步驟在高溫下進行修補基板中因雷射照射而引起之損傷，及f)當摻雜完成時，再次移除由所施覆的膏形成之玻璃層，其中步驟b)至e)可取決於所需摻雜結果以不同順序進行及視需要重複之。雷射照射後之擴散步驟中的溫度處理較佳在750至1100℃範圍內的溫度下進行以進行摻雜，其中在相同時間進行基板中因雷射照射引起之損傷之修補。 The present invention relates to a novel method of directly doping a ruthenium substrate, wherein a) the entire surface or selectively will be suitably used as a sol-gel for forming an oxide layer and comprising at least one selected from the group consisting of boron, Doping paste of doping elements of gallium, germanium, antimony, zinc, tin, phosphorus, titanium, zirconium, lanthanum, nickel, cobalt, iron, lanthanum, cerium, arsenic and lead is printed on the surface of the substrate and dried, b) Repeating this step with a doping paste of the same or different composition as needed, and c) doping by diffusion at a temperature in the range of 750 to 1100 ° C as needed, and d) by laser irradiation Performing doping of the substrate, and e) performing damage to the substrate due to laser irradiation at a high temperature by a tubular furnace step or an in-line diffusion step as needed, and f) when the doping is completed, removing the substrate again The glass layer formed by the applied paste, wherein steps b) to e) may be performed in different orders depending on the desired doping results and repeated as needed. The temperature treatment in the diffusion step after laser irradiation is preferably in the range of 750 to 1100 ° C Doping is performed at a temperature within the circumference, wherein repair of damage due to laser irradiation in the substrate is performed at the same time.

特定言之，然而，本發明亦關於一種如由技術方案2至9表徵之方法，該方法因此代表本發明之一部分。 In particular, however, the invention also relates to a method as characterized by the technical solutions 2 to 9, which thus represents a part of the invention.

特定言之，然而，本發明亦關於藉由此等製程步驟製造之太陽能電池及光伏打元件，其由於本文所述之製程而具有明顯改良之性質，諸如更佳之光輸出及因此提高之效率，亦即，更高之電流生產率。 In particular, however, the present invention is also directed to solar cells and photovoltaic elements fabricated by such process steps, which have significantly improved properties due to the processes described herein, such as better light output and thus improved efficiency, That is, higher current productivity.

圖1展示習知太陽能電池(忽略背側)之前側之圖解及簡化表示(非按比例)。該圖展示兩段式發射體，其係自兩個呈不同薄片電阻之形式的經摻雜區域產生。該等不同薄片電阻可歸因於兩種摻雜分佈之不同分佈深度，及因此一般亦與不同劑量之摻雜劑相關聯。待由此等結構元件製造之太陽能電池之金屬觸點始終與經更強力摻雜之區域接觸。 Figure 1 shows a schematic and simplified representation (not to scale) of the front side of a conventional solar cell (ignoring the back side). The figure shows a two-stage emitter produced from two doped regions in the form of different sheet resistances. These different sheet resistances can be attributed to different distribution depths of the two doping profiles, and thus are generally associated with different doses of dopant. The metal contacts of the solar cell to be fabricated from such structural elements are always in contact with the more strongly doped regions.

圖2展示根據本發明之藉由矽晶圓上可印刷摻雜膏之雷射輻射處理(請參閱圖3)引起之摻雜製程之圖解及簡化表示(非按比例)，其中可使用不同組成之可印刷摻雜膏(諸如，例如，含有不同濃度摻雜劑之摻雜膏)。 2 shows a schematic and simplified representation (not to scale) of a doping process caused by laser radiation treatment of a printable dopant paste on a germanium wafer (see FIG. 3) in accordance with the present invention, wherein different compositions may be used The paste can be printed (such as, for example, a dopant paste containing different concentrations of dopants).

圖3展示根據本發明之藉由矽晶圓上可印刷摻雜膏之雷射輻射處理引起之摻雜製程之圖解及簡化表示(未按比例)。 3 shows a graphical representation and a simplified representation (not to scale) of a doping process caused by laser radiation treatment of a printable dopant paste on a germanium wafer in accordance with the present invention.

圖4展示根據本發明之考慮到產生不同極性之相鄰摻雜而藉由矽晶圓上可印刷摻雜膏之雷射輻射處理引起之摻雜製程之圖解及簡化表示(未按比例)，該等相鄰摻雜在各情況中係以兩段式(淡色=弱摻雜，暗色=更強之摻雜)進行。 4 shows a graphical and simplified representation (not to scale) of a doping process caused by laser radiation treatment of a printable dopant paste on a germanium wafer in consideration of generating adjacent doping of different polarities in accordance with the present invention, These adjacent dopings are carried out in each case in two stages (light color = weak doping, dark color = stronger doping).

圖5展示根據本發明之考慮到產生不同極性之相鄰摻雜而藉由矽晶圓上可印刷摻雜膏之雷射輻射處理引起之摻雜製程之圖解及簡化表示(未按比例)，該等相鄰摻雜在各情況中係以兩段式(淺色=弱摻雜，暗色=更強之摻雜)進行。經印刷並乾燥之摻雜劑源可以可能的頂層在一種可能的製程變體中密封。可特別在雷射束處理之後亦及在雷射束處理之前將頂層施加至經印刷並乾燥之摻雜劑源。在本發明圖5中，頂層已在雷射束處理後藉由熱擴散補充經印刷並乾燥之摻雜劑源。 5 shows a schematic and simplified representation (not to scale) of a doping process caused by laser radiation treatment of a printable dopant paste on a germanium wafer in consideration of generating adjacent doping of different polarities in accordance with the present invention, These adjacent dopings are carried out in two cases (light color = weak doping, dark color = stronger doping) in each case. The printed and dried dopant source can be sealed in a possible process variant with a possible top layer. The top layer can be applied to the printed and dried dopant source, particularly after the laser beam treatment and prior to the laser beam treatment. In Figure 5 of the present invention, the top layer has been supplemented with a printed and dried dopant source by thermal diffusion after laser beam processing.

圖6展示隨各種擴散條件：在雷射擴散之後及在雷射擴散及隨後的熱擴散之後變化之ECV摻雜分佈。作為經印刷並乾燥之摻雜膏之雷射照射的結果，如可參考參考受照射場33(LD，33)中之摻雜分佈測得的值清楚地展示，已引起矽晶圓之摻雜。 Figure 6 shows the ECV doping profile as a function of various diffusion conditions: after laser diffusion and after laser diffusion and subsequent thermal diffusion. As a result of the laser irradiation of the printed and dried doping paste, as clearly shown by reference to the value measured by the doping profile in the irradiated field 33 (LD, 33), the doping of the germanium wafer has been caused. .

原則上，電荷-載子之產生之增加改善太陽能電池之短路電流。雖然熟悉此項技術者明瞭似乎仍存在由於許多技術優點相比習知太陽能電池改良性能之可能性，然而其不再係非尋常的，此乃因甚至用作間接半導體之矽基板能夠吸收入射太陽能輻射之主要部分。不過使用例如聚集太陽能輻射之太陽能電池概念時電流生產率之顯著增加仍係可能的。表徵太陽能電池之性能的另一參數為所謂的開端電壓或即電池能夠遞送之最大電壓。此電壓之水平係取決於若干因素，尤其取決於最大可達成短路電流密度，但亦取決於所謂的有效電荷-載子壽命，該有效電荷-載子壽命本身為矽之材料品質之函數，但亦為半導體之表面之電子鈍化之函數。特定言之，兩種最後所述性質及參數在高效率太陽能電池架構之設計中扮演重要角色且最初在造成提高新穎類型之太陽能電池性能之可能性之主要因素當中。已在導論中提及一些新穎類型之太陽能電池。回到所謂的選擇性或兩段式發射體(請參閱圖1)之概念，可如下參考其在效率提高背後之機制圖解概述原理，參考圖1： In principle, the increase in charge-carrier generation improves the short-circuit current of the solar cell. Although it is clear to those skilled in the art that there are still many possibilities for improving the performance of conventional solar cells due to many technical advantages, they are no longer unusual, because even a substrate used as an indirect semiconductor can absorb incident solar energy. The main part of radiation. However, a significant increase in current productivity when using a solar cell concept such as solar radiation is still possible. Another parameter characterizing the performance of a solar cell is the so-called open end voltage or the maximum voltage that the battery can deliver. The level of this voltage depends on several factors, in particular on the maximum achievable short-circuit current density, but also on the so-called effective charge-carrier lifetime, which is itself a function of the material quality of the crucible, but It is also a function of the electronic passivation of the surface of the semiconductor. In particular, the two last described properties and parameters play an important role in the design of high efficiency solar cell architectures and are initially among the major factors contributing to the potential for improving the performance of novel types of solar cells. Some novel types of solar cells have been mentioned in the introduction. Returning to the concept of a so-called selective or two-stage emitter (see Figure 1), reference can be made to its schematic diagram behind the mechanism of efficiency improvement, see Figure 1:

太陽能電池之前側至少大致上提供有所謂的發射體摻雜。此發射體摻雜可係n型或p型中任一者，根據所使用的基底材料(該基底接著以相反方式進行摻雜)而定。與基底接觸之發射體形成pn接面，該pn接面能夠收集並分離在太陽能電池中通過存於接面之上之電場形成之電荷載子。此處少數電荷載子自基底被驅入發射體中，於該處其接著歸屬多數電荷載子。此等多數電荷載子進一步輸送於發射的區中及可通過位於發射體區上之電觸點從電池中呈電流輸出。對應之情況適用於少數電荷載子，該等少數電荷載子在發射體中產生及可通過基底輸送離開。與基底中之少數電荷載子對比，在發射體中，此等在該區域中具有至多僅數奈秒之極短的有效載子壽命。此源自少數電荷載子之重組率簡而言之係與矽中各別區域之摻雜濃度成反比例之事實；亦即，太陽能電池之發射體區域(其本身代表矽中之高度摻雜區)中各別少數電荷載子之載子壽命可係極短的，亦即，比在相對低程度上進行摻雜之基底中短很多。出於此原因，矽晶圓之發射體區域若可能則製成相對地薄，亦即，總體上具有相比基板之厚度很小的深度，使得產生於此區域中之少數電荷載子(彼等則具有極短的壽命，此係系統中固有的)具有足夠的機會或事實上時間以實現pn接面且在後者收集並分離且接著作為多數電荷載子驅入基底中。多數電荷載子一般具有應視為無窮大之載子壽命。若期望使此製程更有效率，則不可避免地必須要減少發射體摻雜及減小深度使得可產生更多的具有更長載子壽命之少數電荷載子並呈輸送電流之多數電荷載子驅入基底中。相反地，發射體屏蔽來自表面之多數電荷載子。半導體之表面始終極具重組活性。可藉由產生及沉積電子鈍化層極大程度地降低此重組活性(相比例如尚未鈍化之表面降低多達七個數量級，自有效表面重組率測得)。 The front side of the solar cell is at least substantially provided with so-called emitter doping. This emitter doping can be either either n-type or p-type, depending on the substrate material used, which is then doped in the opposite manner. The emitter in contact with the substrate forms a pn junction that is capable of collecting and separating charge carriers formed in the solar cell by an electric field deposited on the junction. Here a small number of charge carriers are driven from the substrate into the emitter where they then belong to most charge carriers. Most of the charge carriers are further transported in the region of the emission and can be output as current from the battery via electrical contacts located on the emitter region. The corresponding situation applies to a small number of charge carriers that are generated in the emitter and that can be transported away through the substrate. In contrast to the few charge carriers in the substrate, in the emitter these have an extremely short effective carrier lifetime of only a few nanoseconds in the region. The recombination rate derived from a minority of charge carriers is, in short, inversely proportional to the doping concentration of the respective regions of the crucible; that is, the emitter region of the solar cell (which itself represents a highly doped region in the crucible) The carrier lifetime of each of the few charge carriers can be extremely short, that is, much shorter than in a relatively low degree doping substrate. For this reason, the emitter region of the germanium wafer is made relatively thin if possible, that is, generally has a depth that is less than the thickness of the substrate, resulting in a small number of charge carriers in this region (the other And so on, with a very short lifetime, inherent in this system) has sufficient opportunity or de facto time to implement the pn junction and in the latter collect and separate and join the majority of the charge carriers into the substrate. Most charge carriers generally have a carrier lifetime that should be considered infinite. If it is desired to make this process more efficient, it is inevitable that the emitter doping and the depth reduction must be such that a larger number of charge carriers with longer carrier lifetimes can be generated and most of the charge carriers are delivered. Drive into the substrate. Conversely, the emitter shields most of the charge carriers from the surface. The surface of the semiconductor is always very reorganized Sex. This recombination activity can be greatly reduced by the generation and deposition of an electron passivation layer (as measured by, for example, a surface that has not been passivated by up to seven orders of magnitude, as measured by the effective surface recombination rate).

在一個態樣中，產生具有足夠陡的摻雜分佈之發射體支持表面之鈍化： In one aspect, an emitter support surface with a sufficiently steep doping profile is produced:

此等區域中少數電荷載子之載子壽命變得如此短以致其平均壽命僅允許極低的準靜態濃度。由於電荷載子之重組係基於使少數電荷載子及多數電荷載子在一起，故此情況中存在僅過少的能夠與多數電荷載子直接在表面重組之少數電荷載子。 The carrier lifetime of a few charge carriers in such regions becomes so short that their average lifetime allows only very low quasi-static concentrations. Since the recombination of charge carriers is based on the fact that a small number of charge carriers and a plurality of charge carriers are combined, there are only a small number of charge carriers that can be directly recombined with the majority of charge carriers on the surface.

通過介電鈍化層實現相比發射體之電子鈍化明顯佳的電子鈍化。另一方面，然而，發射體仍部分地造成產生與太陽能電池之電觸點，該等電觸點必須是歐姆觸點。其等係藉由將接觸材料(一般而言係銀)驅入矽結晶中獲得，其中所謂的矽-銀接觸電阻取決於待接觸之表面處矽的摻雜程度。矽之摻雜越高，接觸電阻可越小。矽上之金屬觸點亦具極強重組活性，基於該原因，在金屬觸點下方之矽區應具有極強且極深之發射體摻雜。此摻雜屏蔽來自金屬觸點之少數電荷載子，及同時達成低接觸電阻及因此達成極佳的歐姆導電性。 Electronic passivation, which is significantly better than electronic passivation of the emitter, is achieved by the dielectric passivation layer. On the other hand, however, the emitter still partially creates electrical contacts with the solar cells, which must be ohmic contacts. They are obtained by driving a contact material (generally silver) into a ruthenium crystal, wherein the so-called yttrium-silver contact resistance depends on the degree of doping of ruthenium at the surface to be contacted. The higher the doping of germanium, the smaller the contact resistance. The metal contacts on the crucible also have extremely strong recombination activity. For this reason, the crucible region below the metal contacts should have extremely strong and extremely deep emitter doping. This doping shields a small number of charge carriers from the metal contacts and at the same time achieves low contact resistance and thus excellent ohmic conductivity.

相反，在入射陽光直接落在太陽能電池上的所有位置中，發射體摻雜應極低且相對平坦(亦即，不極深)使得可藉由入射太陽輻射產生具有足夠壽命之足量少數電荷載子並通過在pn接面處分離作為多數電荷載子驅入基底中。 Conversely, in all locations where incident sunlight falls directly on the solar cell, the emitter doping should be extremely low and relatively flat (ie, not very deep) such that a sufficient amount of charge with sufficient lifetime can be produced by incident solar radiation. The carrier is driven into the substrate by separation at the pn junction as a majority of charge carriers.

驚人地，實驗現已顯示具有兩個直接位於金屬觸點下方之不同發射體摻雜(更確切而言，一個區域具有淺摻雜及一個區域具有極深且極高之摻雜)之太陽能電池具有顯著更高的效率。該概念稱為選擇性或兩段式發射體。對應之概念係基於所謂的選擇性背表面場。因此，必須在太陽能電池之表面結構化之摻雜中達成兩個經不同摻雜之區域。 Surprisingly, experiments have now shown that there are two solar cells that are directly doped under the metal contacts (more precisely, one region has shallow doping and one region has extremely deep and very high doping). Significantly higher efficiency. This concept is called a selective or two-stage emitter. The corresponding concept is based on the so-called selective back surface field. Therefore, two differently doped regions must be achieved in the doping of the surface structuring of the solar cell.

該等實驗已顯示特定言之可藉由達成此等結構化摻雜來實現本發明目標。導論中所述之摻雜製程一般係基於淺沉積亦及沉積的摻雜劑之淺驅入。一般不提供選擇性觸發以達成不同摻雜強度且亦無法在無進一步之結構化及遮蔽製程下輕易地達成。 These experiments have shown that the object of the invention can be achieved by achieving such structured doping in particular. The doping process described in the introduction is generally based on shallow deposition and shallow drive of deposited dopants. Selective triggering is generally not provided to achieve different doping strengths and is not easily achieved without further structuring and masking processes.

因此，本發明製程包括相比上文所述之兩段式或選擇性發射體結構簡化之生產製程。更一般而言，該製程描述一種自矽基板之表面開始產生經不同強度及深度摻雜之區(n型及p型)之簡化，其中術語「強度」可(但不一定必須)描述可達成之表面濃度之水平。就以兩段式摻雜之區而言，此在兩種情況中可相同。摻雜之不同強度接著通過摻雜劑之不同穿透深度及各別摻雜劑之相關聯之不同積分劑量產生。此處所述之製程因此在相同時間提供具有至少一種具有兩段式摻雜之結構模體之太陽能電池結構之廉價且簡化之製法。先前已提及對應之太陽能電池結構。 Thus, the process of the present invention includes a simplified manufacturing process compared to the two-stage or selective emitter structure described above. More generally, the process describes a simplification of the formation of regions of different strength and depth doping (n-type and p-type) from the surface of the substrate, wherein the term "strength" may (but not necessarily) describe achievable The level of surface concentration. In the case of a two-stage doped region, this may be the same in both cases. The different intensities of the doping are then produced by different penetration depths of the dopants and associated different integrated doses of the respective dopants. The process described herein thus provides an inexpensive and simplified process for fabricating a solar cell structure having at least one structural mold having two-stage doping at the same time. The corresponding solar cell structure has been previously mentioned.

.PERC太陽能電池 .PERC solar cell

.PERT太陽能電池 .PERT solar cell

.PERL太陽能電池 .PERL solar cell

.MWT太陽能電池 .MWT solar cell

.背表面接觸電池 . Back surface contact battery

藉由使用可簡單且廉價地印刷之摻雜介質使得簡化生產製程可行。摻雜介質至少對應於彼等揭示於專利申請案WO 2012/119686 A1及WO 2014/101989 A1中者，但可具有不同的組成及調配物。 Simplified production processes are made possible by the use of doping media that can be printed simply and inexpensively. The doping medium corresponds at least to those disclosed in the patent applications WO 2012/119686 A1 and WO 2014/101989 A1, but may have different compositions and formulations.

摻雜介質具有在25l/s之剪切速率及23℃之溫度下測得較佳大於500mPa*s之黏度，及因此由於其黏度及其其他調配性質而極適合網版印刷之個別要求。其等係假塑性及另外亦可具有觸變表現。可印刷之摻雜介質係藉助習知網版印刷機器施加至整個待摻雜表面。在本說明過程中提及典型但非限制性之印刷設置。於隨後在介於50℃與750℃之間，較佳介於50℃與500℃之間，尤佳介於50℃與400℃之間之溫度範圍內，使用待相繼進行之一或多個加熱步驟(通過階梯函數加熱)及/或加熱升溫乾燥經印刷之摻雜介質且壓實以進行玻璃化，導致形成具有厚達500nm厚度之耐處理且耐磨之層。為達成依此方式處理之基板之兩段式摻雜之進一步的處理可於隨後包括兩種可能的製程順序，該等製程順序將簡短地概述於下文中。 The doping medium has a viscosity of preferably greater than 500 mPa*s measured at a shear rate of 25 l/s and a temperature of 23 ° C, and thus is highly suitable for the web due to its viscosity and other blending properties. Individual requirements for printing. They are pseudoplastic and may also have thixotropic properties. The printable doping medium is applied to the entire surface to be doped by means of a conventional screen printing machine. Typical but non-limiting print settings are mentioned in the course of this description. Subsequently, one or more heatings to be successively carried out are used in a temperature range between 50 ° C and 750 ° C, preferably between 50 ° C and 500 ° C, particularly preferably between 50 ° C and 400 ° C. The step (heating by a step function) and/or heating to dry the printed doping medium and compacting for vitrification results in the formation of a resistant and wear resistant layer having a thickness of up to 500 nm. Further processing to achieve two-stage doping of the substrate processed in this manner may then include two possible process sequences, which will be briefly summarized below.

將僅針對於矽基板可能摻雜硼作為摻雜劑描述製程順序。雖然實施該等製程順序之必要性略偏離，但類似描述亦可應用於作為摻雜劑之磷。 The process sequence will be described only for the possibility that the germanium substrate may be doped with boron as a dopant. Although the necessity to implement these process sequences is slightly deviated, similar descriptions can be applied to phosphorus as a dopant.

1.經印刷至表面上、壓實並玻璃化之層之熱處理在介於750℃與1100℃之間，較佳介於850℃與1100℃之間，尤佳介於850℃與1000℃之間範圍內之溫度下進行。因此，對矽具有摻雜作用之原子(諸如硼)係藉由矽熱還原其在基板表面上之氧化物(只要摻雜劑呈游離及/或結合氧化物形式存於摻雜劑源之基質中即可)釋放至基板，藉此矽基板之導電性因摻雜之開始而尤其有利地受到影響。在此，尤其有利的是，由於經印刷之基板之熱處理，摻雜劑被輸送至深達1μm之深度，取決於處理之持續時間而改變，及達成小於10Ω/sqr之薄片電阻。在此摻雜劑之表面濃度可採用大於或等於1*10¹⁹至大於1*10²¹個原子/cm³之值及取決於用於可印刷氧化物介質中之摻雜劑之類型而改變。就以硼摻雜而言，薄的所謂的硼表層(其一般被視作由一旦超出矽中硼之溶解度限值(該限值通常為3至4*10²⁰個原子/cm³)即形成的硼化矽組成之相)形成於矽表面上。此硼表層之形成係取決於所採用的擴散條件，但不能防止落在經典氣相擴散及摻雜之範圍內。然而，已發現可印刷摻雜介質之調配物之選擇可對硼表層之形成及形成厚度產生相當大的影響。存於矽基板上之硼表層可借助於適宜之雷射照射用作用於局部選擇性地進一步驅入摻雜劑硼而深化摻雜分佈之摻雜劑源。對此，然而，必須從擴散及摻雜爐移出依此方式處理之晶圓且借助於雷射照射處理。至少殘留的但未暴露於雷射照射之矽晶圓表面區域於隨後仍具有未處理之硼表層。由於在許多研究中已證明硼表層對矽表面之電子表面鈍化能力起反作用，故似乎必須消除硼表層以防不利的擴散及摻雜製程。 1. The heat treatment by printing onto the surface, compacted and vitrified layer is between 750 ° C and 1100 ° C, preferably between 850 ° C and 1100 ° C, particularly preferably between 850 ° C and 1000 ° C Perform at temperatures within the range. Therefore, an atom having a doping effect (such as boron) reduces its oxide on the surface of the substrate by heat (as long as the dopant is present in the matrix of the dopant source in the form of free and/or bound oxide). The substrate can be released to the substrate, whereby the conductivity of the germanium substrate is particularly advantageously affected by the onset of doping. Here, it is particularly advantageous that, due to the heat treatment of the printed substrate, the dopant is transported to a depth of up to 1 μm, depending on the duration of the treatment, and a sheet resistance of less than 10 Ω/sqr is achieved. The surface concentration of the dopant herein may be greater than or equal to 1*10 ¹⁹ to greater than 1*10 ²¹ atoms/cm ³ and may vary depending on the type of dopant used in the printable oxide medium. In the case of boron doping, a thin so-called boron skin layer (which is generally considered to be formed by the solubility limit of boron beyond the cerium (which is usually 3 to 4*10 ²⁰ atoms/cm ³ ) is formed. The phase of the lanthanum boride is formed on the surface of the crucible. The formation of this boron surface layer depends on the diffusion conditions employed, but does not prevent it from falling within the scope of classical vapor phase diffusion and doping. However, it has been found that the choice of formulation for the printable dopant medium can have a substantial effect on the formation and thickness of the boron surface layer. The boron skin layer deposited on the ruthenium substrate can be used as a dopant source for deepening the doping profile by means of suitable laser illumination for locally selectively driving the dopant boron. In this regard, however, the wafers treated in this manner must be removed from the diffusion and doping furnace and processed by means of laser irradiation. At least the surface area of the wafer that remains but is not exposed to laser illumination subsequently has an untreated boron surface layer. Since the boron surface layer has been shown to be counterproductive to the electronic surface passivation ability of the tantalum surface in many studies, it appears that the boron surface layer must be eliminated to prevent unfavorable diffusion and doping processes.

可通過各種氧化製程，諸如，例如，低溫氧化(通常在介於600℃與850℃之間之溫度下)，其係低於擴散及摻雜溫度之短暫氧化步驟，其中氣體氛圍以特定及可控方式藉由富集氧、或藉由在擴散及摻雜製程中恆定驅入少量氧調整，達成成功地消除該相。 It can be passed through various oxidation processes, such as, for example, low temperature oxidation (typically at temperatures between 600 ° C and 850 ° C), which is a transient oxidation step below the diffusion and doping temperatures, where the gas atmosphere is specific and The control method achieves successful elimination of the phase by enriching oxygen or by constantly driving a small amount of oxygen in the diffusion and doping processes.

氧化條件之選擇影響所獲得之摻雜分佈：就低溫氧化而言，在足夠低的溫度下僅硼表層氧化，及發生少許表面摻雜劑硼(其原則上更佳地溶解於氧化期間形成的二氧化矽中)耗乏，同時於其餘兩個氧化步驟中，不僅僅硼表層而且因高度摻雜而具有顯著增加之氧化速率(速率之增加倍數高達200)之實際需要的經摻雜之矽之部分亦被氧化並消耗。顯著除去摻雜劑可在表面發生，此需要熱後處理，熱後處理係已擴散至矽中之摻雜劑原子之分佈或驅入步驟。然而，在此情況中，據推測摻雜劑源僅供應少量或不供應其他摻雜劑至矽。亦可進行矽表面及存於其上之硼表層之氧化及藉由額外引入蒸汽及/或含氯蒸氣及氣體明顯地加速。一消除硼表層之替代性方法由借助於濃硝酸之濕化學氧化及隨後蝕刻於表面上所獲得之二氧化矽層組成。此種處理必須以複數個級聯方式進行以完全消除硼表層，其中此種級聯並未伴隨顯著表面摻雜劑耗乏。 The choice of oxidation conditions affects the doping profile obtained: in the case of low temperature oxidation, only the surface layer of boron is oxidized at a sufficiently low temperature, and a small amount of surface dopant boron (which is in principle better dissolved during oxidation) In the cerium oxide, it is depleted, and in the remaining two oxidation steps, not only the boron surface layer but also the doped cadmium which has a significantly increased oxidation rate (the rate of increase of up to 200) is highly doped. Parts are also oxidized and consumed. Significant removal of the dopant can occur at the surface, which requires thermal post treatment, which is a diffusion or diffusion step of the dopant atoms that have diffused into the crucible. However, in this case, it is presumed that the dopant source supplies little or no other dopants to the germanium. Oxidation of the surface of the crucible and the surface layer of boron present thereon can also be effected by the additional introduction of steam and/or chlorine-containing vapors and gases. An alternative method of eliminating the boron skin consists of a layer of ruthenium dioxide obtained by wet chemical oxidation with concentrated nitric acid and subsequent etching on the surface. This treatment must be performed in a number of cascades to completely eliminate the boron skin layer, where such cascading is not accompanied by significant surface dopant depletion.

在此就產生具有局部選擇性或兩段式摻雜之區域所概述之順序係以下列至少十個步驟區分： The sequence outlined in the region with local or two-stage doping is generated here. It is distinguished by at least ten steps:

印刷摻雜劑源→ Printing dopant source →

壓實→ Compaction →

引入至摻雜爐中→ Introduced into the doping furnace →

基板之熱擴散及摻雜→ Thermal diffusion and doping of the substrate →

移出樣品→ Remove the sample →

雷射照射以自硼表層選擇性摻雜→ Laser irradiation is selectively doped from the surface layer of boron →

引入樣品至爐中→ Introduce the sample into the furnace →

氧化移除硼表層→ Oxidation removes boron surface layer →

進一步進行驅入處理→ Further drive-in processing →

自爐移出。 Removed from the furnace.

2.對施加於整個表面之上之摻雜劑乾燥及壓實後，通過雷射輻射局部照射基板。對此，存於表面上之層不一定必須完全壓實並玻璃化。藉由適宜地選擇表徵雷射輻射處理之參數，諸如脈衝長度、輻射焦點中之照射面積、使用脈衝雷射輻射時之重複速率，摻雜劑源之經印刷並乾燥之層可釋放存於其中之具有摻雜作用之摻雜劑至較佳位於經印刷之層下方之周圍矽。藉由選擇偶聯至經印刷之基板之表面上之雷射能，可特定影響並控制基板之薄片電阻。在此，較高的雷射能產生較低的薄片電阻，此簡而言之對應於較高劑量之引入的摻雜劑及較大深度之摻雜分佈。若需要，則可於隨後自晶圓之表面藉助含有氫氟酸亦及氫氟酸與磷酸二者之水溶液或藉助對應之基於有機溶劑的溶液、亦及通過使用此兩上述蝕刻溶液之混合物移除摻雜劑源之經印刷之層而無殘留。可在使用蝕刻混合物期間藉由超音波作用加速並促進移除摻雜劑源。或者，經印刷之摻雜劑源可留在矽晶圓之表面上。依此方式塗佈之晶圓可於習知的摻雜爐中藉由熱引起之擴散在整個經塗佈矽晶圓表面上進行摻雜。此種摻雜可在常用的摻雜爐中進行。此等摻雜爐可為管狀爐(水平及/或垂直)或水平工作之直流爐(其中所使用的氣體氛圍可特別設定)中任何一種。由於摻雜劑自經印刷之摻雜劑源因熱引起擴散至晶圓下層矽中，達成整個晶圓之摻雜且薄片電阻發生改變。摻雜之程度係取決於所採用的各別製程參數，諸如，例如，製程溫度、平線區時間、氣體流速、所使用的加熱源之類型及為設定各別製程溫度之升溫速率。在此種類型之製程中，取決於藉助雷射束摻雜及使用根據本發明之摻雜膏調配物處理之區域，通常以30分鐘之擴散時間在950℃下且利用五標準公升N₂/分鐘之氣體流速達成約75ohm/sqr之薄片電阻。就上述處理而言，可視需要在高達500℃之溫度下預乾燥晶圓。如上文已在1)下更詳細地描述擴散後緊接著氧化移除所謂的硼表層，但亦視需要再分佈已溶於矽中之硼以調適並控制可產生之摻雜分佈。基於方才所概述之程序，可重複性地獲得上述薄片電阻。關於性能及對應之其他製程參數之進一步的詳細內容更詳細地述於以下實例中。 2. After the dopant applied over the entire surface is dried and compacted, the substrate is locally illuminated by laser radiation. In this regard, the layer deposited on the surface does not have to be completely compacted and vitrified. By suitably selecting parameters that characterize the laser radiation treatment, such as pulse length, illumination area in the radiation focus, and repetition rate when using pulsed laser radiation, the printed and dried layer of the dopant source can be released therein. The dopant having a doping effect is preferably located around the periphery of the printed layer. The sheet resistance of the substrate can be specifically influenced and controlled by selecting the laser energy coupled to the surface of the printed substrate. Here, a higher laser can produce a lower sheet resistance, which in short corresponds to a higher dose of introduced dopant and a larger depth doping profile. If necessary, it can be subsequently transferred from the surface of the wafer by means of an aqueous solution containing hydrofluoric acid and hydrofluoric acid and phosphoric acid or by a corresponding organic solvent-based solution, and by using a mixture of the above two etching solutions. The printed layer is removed except for the dopant source. The removal of the dopant source can be accelerated and facilitated by ultrasonication during use of the etch mixture. Alternatively, the printed dopant source can remain on the surface of the germanium wafer. The wafer coated in this manner can be doped over the entire coated wafer surface by heat-induced diffusion in a conventional doping furnace. Such doping can be carried out in a conventional doping furnace. These doping furnaces may be any of a tubular furnace (horizontal and/or vertical) or a horizontally operated direct current furnace in which the gas atmosphere used may be specially set. Since the dopant is diffused into the underlying layer of the wafer from the printed dopant source due to heat, doping of the entire wafer is achieved and the sheet resistance is changed. The degree of doping depends on the individual process parameters employed, such as, for example, process temperature, flat line time, gas flow rate, type of heat source used, and rate of temperature increase for setting individual process temperatures. In this type of process, depending on the area treated by the laser beam doping and using the doping paste formulation according to the invention, typically at a diffusion time of 30 minutes at 950 ° C and using five standard liters of N ₂ / The gas flow rate in minutes reached a sheet resistance of about 75 ohm/sqr. For the above treatment, it is possible to pre-dry the wafer at temperatures up to 500 °C. The so-called boron skin layer is removed as described above in more detail below under diffusion, but the boron which has been dissolved in the crucible is also redistributed as needed to adapt and control the doping profile that can be produced. The above sheet resistance is reproducibly obtained based on the procedure outlined by the party. Further details regarding performance and other process parameters are described in more detail in the examples below.

先前已通過雷射束處理界定之區域及已溶於此等區域中之摻雜劑亦因摻雜劑之熱引起擴散而受刺激進一步擴散。由於此種額外的擴散，摻雜劑能夠在此等點更深地穿透至矽中且相應地形成更深的摻雜分佈。同時，可於隨後將摻雜劑自位於晶圓表面上之摻雜劑源供應至矽。相比僅在摻雜爐中經過熱引起之擴散之其等區域具有明顯更深之摻雜分佈亦及明顯更高劑量之摻雜劑硼之經摻雜之區因此形成於先前經過雷射輻射處理之區域中。換言之，發生兩段式摻雜，亦稱為選擇性摻雜。例如，後者可用於製造具有選擇性發射體之太陽能電池，用於製造雙面太陽能電池(具有選擇性發射體/均勻(單段式)BSF，具有均勻發射體/選擇性BSF且具有選擇性發射體/選擇性BSF)，用於製造PERT電池，或亦用於製造IBC太陽能電池。 The regions previously defined by the laser beam treatment and the dopants already dissolved in these regions are also stimulated to diffuse further due to the diffusion of heat from the dopant. Due to this additional diffusion, the dopant can penetrate deeper into the crucible at this point and correspondingly form a deeper doping profile. At the same time, the dopant can be subsequently supplied to the germanium from a dopant source located on the surface of the wafer. The doped region with a significantly deeper doping profile and a significantly higher dose of dopant boron compared to the heat-induced diffusion only in the doping furnace is thus formed prior to laser radiation treatment. In the area. In other words, two-stage doping occurs, also known as selective doping. For example, the latter can be used to fabricate solar cells with selective emitters for the fabrication of double-sided solar cells (with selective emitter/uniform (single-segment) BSF, with uniform emitter/selective BSF and selective emission Body/selective BSF) for the manufacture of PERT cells or for the manufacture of IBC solar cells.

類似的原理亦適用於已藉助雷射輻射預處理之矽晶圓之熱引起之後擴散，該等矽晶圓係事先藉助蝕刻清除去經印刷之摻雜劑源。在此情況中，摻雜劑硼被更深地驅入矽中。由於在此製程之前移除經印刷之摻雜劑源，然而，可能無法於隨後再將摻雜劑供應至矽。已溶於矽中之劑量將保持恆定，而經摻雜之區中摻雜劑之平均濃度因分佈深度之增加及相關之摻雜劑之直接表面濃度之降低而降低。此種程序可用於製造IBC太陽能電池。自經乾燥之摻雜膏藉助雷射束摻雜產生具一種極性之條帶伴隨具有相反極性之條帶，後者反過來藉助雷射束摻雜自經印刷並乾燥之含磷摻雜膏獲得。如此就產生具有局部選擇性或兩段式摻雜之區域所概述之順序係以下列至少八個步驟區分： A similar principle applies to the heat of a silicon wafer that has been pretreated with laser radiation. After diffusion, the germanium wafers are previously removed by etching to the printed dopant source. In this case, the dopant boron is driven deeper into the crucible. Since the printed dopant source is removed prior to this process, however, it may not be possible to subsequently supply the dopant to the germanium. The dose that has dissolved in the crucible will remain constant, while the average concentration of dopant in the doped region decreases as the depth of distribution increases and the direct surface concentration of the associated dopant decreases. This procedure can be used to make IBC solar cells. The self-dried dopant paste is doped by means of a laser beam to produce a strip of one polarity with a strip of opposite polarity, which in turn is obtained by laser beam doping from a printed and dried phosphorus-containing doping paste. The sequence outlined in this way to produce regions with local or two-stage doping is distinguished by at least eight steps:

印刷摻雜劑源→ Printing dopant source →

乾燥→ Dry →

自摻雜劑源之雷射照射→ Laser irradiation from a dopant source →

引入至摻雜爐中→ Introduced into the doping furnace →

熱擴散及(進一步)摻雜基板→ Thermal diffusion and (further) doping substrate →

氧化移除硼表層→ Oxidation removes boron surface layer →

進一步進行驅入處理→ Further drive-in processing →

自爐移出樣品(請參閱圖3)。 Remove the sample from the furnace (see Figure 3).

上文所述之此兩種製程級聯代表製造兩段式或所謂的選擇性摻雜之可能性。基於上述實施例及相關數目之待進行之製程步驟基礎上，所述的第二實施例代表更具吸引力且因更少數目之製程步驟而較佳之替代。 The two process cascades described above represent the possibility of making a two-stage or so-called selective doping. Based on the above-described embodiments and the associated number of process steps to be performed, the second embodiment represents a more attractive and preferred alternative to a smaller number of process steps.

在兩實施例中，可藉由選擇各別製程參數，特定言之雷射束處理或雷射束摻雜之其等製程參數來影響經印刷之摻雜劑源之摻雜作用。然而，亦可藉由可印刷摻雜劑源之組成來關鍵性地影響並控制摻雜作用(請參閱圖2)。若需要，則可不僅只藉由使用可印刷摻雜劑源接著使用另一摻雜劑源進行兩段式摻雜，而是，亦可藉由使用兩種可印刷摻雜劑源來產生兩段式摻雜。可特定言之藉由上述實施例通過存於所使用的摻雜劑源中之摻雜劑濃度來特別影響並控制待引入至待摻雜的矽中之摻雜劑之劑量。 In both embodiments, the doping of the printed dopant source can be affected by selecting individual process parameters, such as laser beam processing or laser beam doping. However, doping can also be critically affected and controlled by the composition of the printable dopant source (see Figure 2). If desired, the two-stage doping can be performed not only by using a printable dopant source but also by using another dopant source, but also by using two types. The dopant source is printed to produce a two-stage doping. In particular, the dose of the dopant to be introduced into the crucible to be doped can be particularly influenced and controlled by the above-described embodiments by the concentration of the dopant present in the dopant source used.

如所述，兩段式摻雜亦及結構化摻雜及提供有相反極性之摻雜均可非常容易地以簡單且廉價之方式在矽晶圓上藉由根據本發明之製程使用新穎的仍舊待在下文表徵之可印刷摻雜膏來產生，使得總共僅單一經典高溫步驟(熱引起之擴散)是必要的(請參閱圖4)。 As described, two-stage doping, as well as structured doping and doping with opposite polarity, can be easily and simply and inexpensively used on a germanium wafer by using the novel process according to the present invention. The printable doping paste to be characterized below is produced such that only a single classical high temperature step (heat induced diffusion) is necessary in total (see Figure 4).

相反極性可有利地同時位於晶圓之一側上或位於相對側上，或最終代表兩種上述結構模體之混合物。另外，兩種極性可具有兩段式摻雜區域，但其等不一定必須具有兩種極性。亦可產生極性1具有兩段式摻雜，而極性2不包含兩段式摻雜之結構。此意指本文所述之製程可以極具可變性之方式進行。除對印刷製程期間各別結構溶解之限制及雷射束處理固有的其等限制外，未對提供有相反摻雜之區域之結構設定進一步的限制。圖3、4及5之表示描繪根據本發明之製程之各種實施例： The opposite polarity may advantageously be located on either side of the wafer or on the opposite side, or ultimately a mixture of two of the above structural phantoms. In addition, the two polarities may have two-stage doped regions, but they do not necessarily have to have two polarities. It is also possible to produce a polarity 1 having a two-stage doping and a polarity 2 not comprising a two-stage doping structure. This means that the processes described herein can be performed in a highly variable manner. In addition to the limitations of the dissolution of the individual structures during the printing process and their inherent limitations on the laser beam processing, no further restrictions are placed on the structure providing the regions of opposite doping. 3, 4 and 5 depict various embodiments of a process in accordance with the present invention:

本發明因此包括可簡單地進行以製造具有更有效之電荷產生之太陽能電池、以及製造可廉價地製造之替代性、可印刷摻雜劑源、其於矽基板上之沉積、及其選擇性一段式摻雜亦及選擇性兩段式摻雜之替代性廉價製程。 The present invention thus includes a solar cell that can be easily fabricated to produce more efficient charge generation, and an alternative, printable dopant source that can be fabricated inexpensively, deposited on a germanium substrate, and a selective segment thereof. Doping is also an alternative inexpensive process with selective two-stage doping.

在此矽基板之選擇性摻雜可(但不一定必須)通過組合經印刷並乾燥之摻雜劑源之初始雷射束處理與隨後的熱擴散來實現。矽晶圓之雷射束處理可與對基板本身之損傷相關聯及因此代表此製程因此損傷而存在之固有缺點，該損傷在一些情況中深深地延伸至矽中，無法至少部分地藉由隨後的處理來修補。在本發明製程中，可於雷射束處理後進行熱擴散，此有助於修補輻射引起之損傷。另外，直接於暴露於雷射輻射之區域上沉積以兩段式摻雜之結構之此類型製造中之金屬觸點(請參閱圖1)。矽-金屬界面之特徵通常係極高重組速率(約2*10⁷cm/s)，意指以兩段式摻雜之區域之經強摻雜之區中可能的損傷因電荷-載子壽命對金屬觸點之高階限制而對組件之性能不明顯。 The selective doping of the germanium substrate can be achieved, but not necessarily, by initial laser beam processing in combination with the printed and dried dopant source followed by thermal diffusion. The laser beam treatment of the germanium wafer can be associated with damage to the substrate itself and thus represents an inherent disadvantage of the process, which in this case extends deep into the crucible, at least in part by Subsequent processing to fix. In the process of the present invention, thermal diffusion can be performed after laser beam treatment, which helps to repair damage caused by radiation. In addition, metal contacts in this type of fabrication are deposited directly onto the area exposed to the laser radiation in a two-stage doped structure (see Figure 1). The 矽-metal interface is typically characterized by a very high recombination rate (approximately 2*10 ⁷ cm/s), meaning possible damage in the strongly doped region of the two-doped region due to charge-carrier lifetime High-order limitations on metal contacts are not significant for component performance.

驚人地，已因此發現使用如專利申請案WO 2012/119686 A1及WO 2014/101989 A1中所述之可印刷摻雜膏可提供藉由經印刷並乾燥之介質之雷射束處理直接摻雜矽基板之可能性。 Surprisingly, it has thus been found that the use of printable doping pastes as described in the patent applications WO 2012/119686 A1 and WO 2014/101989 A1 provides direct doping of germanium by laser beam treatment through a printed and dried medium. The possibility of a substrate.

此種摻雜可局部地實現且無需進一步活化摻雜劑，如通常藉由經典熱擴散所達成。在隨後的步驟，即習知的熱擴散中，引入至矽中之摻雜劑可驅入更深或已溶解的摻雜劑可驅入更深，及可於隨後自摻雜劑源轉移更多的摻雜劑至矽中，在後種情況中，引起已溶於矽中之摻雜劑之劑量增加。 Such doping can be achieved locally and without further activation of the dopant, as is typically achieved by classical thermal diffusion. In a subsequent step, known thermal diffusion, the dopant introduced into the crucible can drive deeper or dissolved dopants to drive deeper and can be self-doped later. The dopant source transfers more dopant to the ruthenium, in which case the dose of dopant that has dissolved in the ruthenium is increased.

經印刷至晶圓上並乾燥之摻雜劑可具有均勻的摻雜劑濃度。就此目的而言，可將該摻雜劑源施加至晶圓之整個表面或選擇性地印刷上去。或者，可以任何所需順序將不同組成及不同極性之摻雜劑源印刷至晶圓上。對此，可例如以兩個連續印刷及乾燥步驟處理該等摻雜源。由以下實例再現本發明之較佳實施例。 The dopant printed onto the wafer and dried may have a uniform dopant concentration. For this purpose, the dopant source can be applied to the entire surface of the wafer or selectively printed. Alternatively, dopant sources of different compositions and different polarities can be printed onto the wafer in any desired order. In this regard, the dopant sources can be processed, for example, in two successive printing and drying steps. The preferred embodiment of the present invention is reproduced by the following examples.

如上所述，本發明使得熟悉此項技術者可全面地使用本發明。即使無進一步注釋，將因此推測得，熟悉此項技術者將能最大限度地利用以上說明。 As described above, the present invention enables the present invention to be fully utilized by those skilled in the art. Even without further comments, it will be inferred that those skilled in the art will be able to make the most of the above description.

若有不明事宜，毋庸贅言，應參照所引述之公開案及專利文獻。因此，此等文件被視作本發明之發明內容之一部分。此特別適用於專利申請案WO 2012/119686 A1或WO 2014/101989 A1之發明內容，因為述於此等申請案中之組合物特別適用於本發明。 If there are any unclear matters, it should be noted that the publications and patent documents cited should be referred to. Accordingly, such documents are considered to be part of the inventive content of the present invention. This applies in particular to the inventive content of the patent application WO 2012/119686 A1 or WO 2014/101989 A1, since the compositions described in these applications are particularly suitable for use in the present invention.

為更佳地明瞭及為說明本發明，下文提供屬於保護本發明之範疇內之實例。此等實例亦用來說明可能的變體。因為所述發明原理之一般有效性，然而，該等實例不適合將保護本申請案之範疇縮減至僅限此等實例。 For the purpose of illustrating the invention, the following examples are provided within the scope of the invention. These examples are also used to illustrate possible variations. Because of the general validity of the described principles of the invention, the examples are not intended to limit the scope of the application to the examples.

另外，對熟悉此項技術者毋庸贅言地，在所給的實例亦及在其餘的描述中，存於組合物中之組分含量始終僅總計達整體組合物之100重量%、mol%或體積%，及即使可因所述百分比範圍而出現更高的值，亦不可能超出該值。除非另有指示，否則數據%因此被認為是重量%、mol%或體積%。 In addition, it will be apparent to those skilled in the art that in the examples given and in the remainder of the description, the amount of components present in the composition always amounts to only 100% by weight, mol% or volume of the overall composition. %, and even if a higher value can occur due to the stated percentage range, it is impossible to exceed this value. Unless otherwise indicated, the % data is therefore considered to be wt%, mol% or volume%.

實例以及描述及申請專利範圍中所提供的溫度始終為℃。 The temperatures provided in the examples and descriptions and in the scope of the patent application are always °C.

實例：Example:

實例1：Example 1:

如專利申請案WO 2012/119686 A1及WO 2014/101989 A1中所述，使用具有線直徑25μm之鋼篩(安裝角度22.5°)及乳液厚度10μm，利用110mm/s之刮刀速度、1巴之刮刀壓力及1mm之印刷篩間隔，用硼摻雜膏印刷具有2ohm*cm電阻率之具有磷基區摻雜之紋理化6" CZ晶圓，其中，取決於其他的印刷參數，在600℃下完全乾燥後產生介於100nm與400nm之間之層厚度。於印刷後，在300℃於習知的實驗室加熱板上乾燥經印刷之膏三分鐘。接著在預定場中藉助具有532nm波長之Nd：YAG奈秒雷射及使用作用於經乾燥之摻雜劑源之各種雷射通量處理晶圓。於隨後藉助四點測量及電化學電容-電壓測量(ECV)測定晶圓上各種場之摻雜。晶圓於隨後在使用930℃之惰性氣體氛圍N₂之習知管狀爐中進行熱擴散30分鐘。在擴散之後，但仍舊在爐製程期間，通過在恆定製程溫度下乾燥氧化及藉由控制因引入20體積%O₂至製程室所引起之傾斜，硼擴散期間所形成之硼表層被氧化。在此製程步驟後，藉助稀氫氟酸，樣品晶圓去除位於晶圓上之玻璃及氧化物層及再通過四點測量及電化學電容-電壓測量(ECV)來表徵摻雜作用。經摻雜之樣品之薄片電阻為(依其在圖6之表示中出現之順序-經基區摻雜之晶圓之薄片電阻為160ohm/sqr，僅印刷膏但尚未暴露於雷射輻射之樣品場之薄片電阻為80ohm/sqr)： As described in the patent applications WO 2012/119686 A1 and WO 2014/101989 A1, a steel screen having a wire diameter of 25 μm (mounting angle of 22.5°) and an emulsion thickness of 10 μm are used, with a blade speed of 110 mm/s, a scraper of 1 bar. Pressure and 1 mm screen spacing, printing a 6" CZ wafer with a phosphorus-based doping with a resistivity of 2 ohm*cm with a boron-doped paste, which is completely at 600 °C depending on other printing parameters After drying, a layer thickness between 100 nm and 400 nm is produced. After printing, the printed paste is dried on a conventional laboratory hot plate for three minutes at 300 ° C. Next, in a predetermined field, Nd having a wavelength of 532 nm is used: YAG nanosecond laser and wafer processing using various laser fluxes applied to the dried dopant source. Subsequent measurements of various fields on the wafer were determined by four-point measurement and electrochemical capacitance-voltage measurement (ECV). The wafer was subsequently thermally diffused for 30 minutes in a conventional tubular furnace using an inert gas atmosphere N ₂ at 930 ° C. After diffusion, but still during the furnace process, by drying and oxidizing at a constant process temperature Control due to the introduction of 20% by volume of O ₂ to the process The tilt caused by the chamber, the boron surface layer formed during the diffusion of boron is oxidized. After the process step, the sample wafer is removed by means of dilute hydrofluoric acid, and the glass and oxide layers on the wafer are removed and measured by four points. Electrochemical Capacitance-Voltage Measurement (ECV) is used to characterize the doping effect. The sheet resistance of the doped sample is (in the order in which it appears in the representation of Figure 6 - the sheet resistance of the wafer doped with the base region is 160 ohms) /sqr, the sheet resistance of a sample field that only prints the paste but has not been exposed to laser radiation is 80 ohm/sqr):

測得之薄片電阻隨不同製程程序變化之概述：在雷射擴散之後及在雷射擴散及隨後的熱擴散之後。 An overview of the measured sheet resistance as a function of different process procedures: after laser diffusion and after laser diffusion and subsequent thermal diffusion.

圖6展示隨各種擴散條件變化之ECV摻雜分佈：在雷射擴散之後及在雷射擴散及隨後的熱擴散之後。作為經印刷並乾燥之摻雜膏之雷射照射的結果，如參照參考受照射場33(LD，33)中之摻雜分佈測得的值可清楚地展示，已引起矽晶圓之摻雜。 Figure 6 shows the ECV doping profile as a function of various diffusion conditions: after laser diffusion and after laser diffusion and subsequent thermal diffusion. As a result of the laser irradiation of the printed and dried doping paste, the value measured by reference to the doping profile in the irradiated field 33 (LD, 33) can be clearly shown, which has caused doping of the germanium wafer. .

參考已根據雷射光之不同能量密度進行照射之場之薄片電阻之測定值，可顯示已自經印刷並乾燥之摻雜膏以1.1J/cm²之雷射通量實現不需要於隨後通過熱擴散活化之摻雜。於雷射照射後進行熱擴散僅引起藉由雷射照射達成之摻雜分佈略有降低，此與薄片電組之降低相關聯。以高能量密度之入射雷射光(大於2J/cm²)處理產生出極深且經極強摻雜之區域。 Referring to the measured values of the sheet resistance of the field which has been irradiated according to the different energy densities of the laser light, it can be shown that the paste which has been printed and dried has a laser flux of 1.1 J/cm ² and is not required to pass through the heat. Diffusion activated doping. Thermal diffusion after laser irradiation only causes a slight decrease in the doping profile achieved by laser irradiation, which is associated with a reduction in the sheet electrical group. Treatment with high energy density incident laser light (greater than ² J/cm ² ) produces extremely deep and strongly doped regions.

Claims

一種直接摻雜矽基板之方法，其特徵在於a)於整個表面或選擇性地將適合用作溶膠-凝膠以用於形成氧化物層且包含至少一種選自群組硼、鎵、矽、鍺、鋅、錫、磷、鈦、鋯、釔、鎳、鈷、鐵、鈰、鈮、砷及鉛之摻雜元素之摻雜膏印刷至基板表面上，並乾燥，b)視需要用相同或不同組成之摻雜膏重複此步驟，c)視需要藉由在750至1100℃範圍內的溫度下溫度處理進行藉由擴散之摻雜，d)藉由雷射照射進行基板之摻雜，及e)視需要藉由管狀爐步驟或線上擴散步驟在高溫下進行修補基板中因雷射照射而引起之損傷，及f)當摻雜完成時，再次移除由所施覆的膏形成之玻璃層，其中步驟b)至e)可取決於所需摻雜結果以不同順序進行及視需要重複之。 A method of directly doping a germanium substrate, characterized in that a) is suitable for use as a sol-gel on the entire surface or selectively for forming an oxide layer and comprises at least one selected from the group consisting of boron, gallium, germanium, Doping paste of doping elements of antimony, zinc, tin, phosphorus, titanium, zirconium, lanthanum, nickel, cobalt, iron, lanthanum, cerium, arsenic and lead is printed on the surface of the substrate and dried, b) the same as needed Repeating this step with a different composition of the doping paste, c) doping by diffusion at a temperature in the range of 750 to 1100 ° C as needed, d) doping the substrate by laser irradiation, And e) repairing the damage caused by the laser irradiation in the substrate at a high temperature by a tubular furnace step or an in-line diffusion step as needed, and f) when the doping is completed, removing the paste formed by the applied paste again The glass layer, wherein steps b) to e) can be carried out in different orders depending on the desired doping results and repeated as needed.

如請求項1之方法，其中於用以摻雜基板之雷射照射後在750至1100℃範圍內的溫度下進行溫度處理以藉由擴散摻雜，其中在相同時間進行修補基板中因雷射照射而引起之損傷。 The method of claim 1, wherein the temperature treatment is performed at a temperature ranging from 750 to 1100 ° C after the laser irradiation for doping the substrate to be doped by diffusion, wherein the laser is repaired at the same time. Damage caused by irradiation.

如請求項1或2之方法，其中印刷上去適用於形成氧化物層且包含至少一種選自群組硼、磷、銻、砷及鎵之摻雜元素之摻雜膏。 The method of claim 1 or 2, wherein the doping paste is applied to form an oxide layer and comprises at least one dopant element selected from the group consisting of boron, phosphorus, antimony, arsenic, and gallium.

如請求項1、2及3中任一項之方法，其中該摻雜膏係藉由選自群組網版印刷、柔版印刷、凹版印刷、平版印刷、微接觸印刷、電流體動力施配、輥塗、噴塗、超聲波噴塗、管噴射、雷射轉移印刷、移動印刷、平板網版印刷及旋轉網版印刷之印刷製程印刷上去。 The method of any one of claims 1, 2, and 3, wherein the doping paste is selected from the group consisting of group screen printing, flexographic printing, gravure printing, lithography, microcontact printing, Printing process printing of electrohydrodynamic force distribution, roll coating, spray coating, ultrasonic spraying, tube spraying, laser transfer printing, mobile printing, flat screen printing and rotary screen printing.

如請求項1、2及3中任一項之方法，其中該摻雜膏係藉由網版印刷印刷上去。 The method of any of claims 1, 2, and 3, wherein the doping paste is printed by screen printing.

如請求項1至5中任一項之方法，其中摻雜係在硼擴散但無「硼表層」之氧化製程後直接自經印刷且乾燥之玻璃進行。 The method of any one of claims 1 to 5, wherein the doping is carried out directly from the printed and dried glass after the boron diffusion but without the "boron surface" oxidation process.

如請求項1至6中任一項之方法，其中藉由至少一次兩段式摻雜與僅一次基板熱擴散或高溫處理來製造具有不同摻雜的區域之結構化、高效率太陽能電池。 The method of any one of claims 1 to 6, wherein the structured, high efficiency solar cell having regions of different doping is fabricated by at least one two-stage doping and only one substrate thermal diffusion or high temperature processing.

如請求項1至7中任一項之方法，其中包含至少一種選自群組硼、鎵、矽、鍺、鋅、錫、磷、鈦、鋯、釔、鎳、鈷、鐵、鈰、鈮、砷及鉛之摻雜元素之玻璃層係在步驟a)中藉由氣相沉積借助於PECVD(電漿增強化學氣相沉積)、APCVD(大氣壓化學氣相沉積)、ALD(原子層沉積)或濺鍍以整個表面或選擇性地產生於基板表面上。 The method of any one of claims 1 to 7, comprising at least one selected from the group consisting of boron, gallium, germanium, antimony, zinc, tin, phosphorus, titanium, zirconium, hafnium, nickel, cobalt, iron, strontium, barium The glass layer of the doping element of arsenic and lead is vapor-deposited in step a) by means of PECVD (plasma enhanced chemical vapor deposition), APCVD (atmospheric pressure chemical vapor deposition), ALD (atomic layer deposition) Or sputtering is applied to the entire surface or selectively on the surface of the substrate.

如請求項1至8中任一項之方法，其中該玻璃層係在摻雜完成時借助於氫氟酸移除。 The method of any one of claims 1 to 8, wherein the glass layer is removed by means of hydrofluoric acid upon completion of doping.

一種太陽能電池，其係藉由如請求項1至9中任一項之方法製造。 A solar cell manufactured by the method of any one of claims 1 to 9.

一種光伏打元件，其係藉由如請求項1至9中任一項之方法製造。 A photovoltaic element produced by the method of any one of claims 1 to 9.